92dbac4cee8bebcfa2df72e5cbdc4bd6764b8b3e
[exim.git] / src / src / smtp_in.c
1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
4
5 /* Copyright (c) University of Cambridge 1995 - 2017 */
6 /* See the file NOTICE for conditions of use and distribution. */
7
8 /* Functions for handling an incoming SMTP call. */
9
10
11 #include "exim.h"
12 #include <assert.h>
13
14
15 /* Initialize for TCP wrappers if so configured. It appears that the macro
16 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
17 including that header, and restore its value afterwards. */
18
19 #ifdef USE_TCP_WRAPPERS
20
21 #if HAVE_IPV6
22 #define EXIM_HAVE_IPV6
23 #endif
24 #undef HAVE_IPV6
25 #include <tcpd.h>
26 #undef HAVE_IPV6
27 #ifdef EXIM_HAVE_IPV6
28 #define HAVE_IPV6 TRUE
29 #endif
30
31 int allow_severity = LOG_INFO;
32 int deny_severity = LOG_NOTICE;
33 uschar *tcp_wrappers_name;
34 #endif
35
36
37 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
38 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
39 commands that accept arguments, and this in particular applies to AUTH, where
40 the data can be quite long. More recently this value was 2048 in Exim;
41 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
42 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
43 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
44 we need room to handle large base64-encoded AUTHs for GSSAPI.
45 */
46
47 #define SMTP_CMD_BUFFER_SIZE 16384
48
49 /* Size of buffer for reading SMTP incoming packets */
50
51 #define IN_BUFFER_SIZE 8192
52
53 /* Structure for SMTP command list */
54
55 typedef struct {
56 const char *name;
57 int len;
58 short int cmd;
59 short int has_arg;
60 short int is_mail_cmd;
61 } smtp_cmd_list;
62
63 /* Codes for identifying commands. We order them so that those that come first
64 are those for which synchronization is always required. Checking this can help
65 block some spam. */
66
67 enum {
68 /* These commands are required to be synchronized, i.e. to be the last in a
69 block of commands when pipelining. */
70
71 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
72 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
73 ETRN_CMD, /* This by analogy with TURN from the RFC */
74 STARTTLS_CMD, /* Required by the STARTTLS RFC */
75 TLS_AUTH_CMD, /* auto-command at start of SSL */
76
77 /* This is a dummy to identify the non-sync commands when pipelining */
78
79 NON_SYNC_CMD_PIPELINING,
80
81 /* These commands need not be synchronized when pipelining */
82
83 MAIL_CMD, RCPT_CMD, RSET_CMD,
84
85 /* This is a dummy to identify the non-sync commands when not pipelining */
86
87 NON_SYNC_CMD_NON_PIPELINING,
88
89 /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and
90 processed the message is sent using a series of BDAT commands"
91 implies that BDAT should be synchronized. However, we see Google, at least,
92 sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for
93 processing of the RCPT response(s). We shall do the same, and not require
94 synch for BDAT. Worse, as the chunk may (very likely will) follow the
95 command-header in the same packet we cannot do the usual "is there any
96 follow-on data after the command line" even for non-pipeline mode.
97 So we'll need an explicit check after reading the expected chunk amount
98 when non-pipe, before sending the ACK. */
99
100 BDAT_CMD,
101
102 /* I have been unable to find a statement about the use of pipelining
103 with AUTH, so to be on the safe side it is here, though I kind of feel
104 it should be up there with the synchronized commands. */
105
106 AUTH_CMD,
107
108 /* I'm not sure about these, but I don't think they matter. */
109
110 QUIT_CMD, HELP_CMD,
111
112 #ifdef SUPPORT_PROXY
113 PROXY_FAIL_IGNORE_CMD,
114 #endif
115
116 /* These are specials that don't correspond to actual commands */
117
118 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
119 TOO_MANY_NONMAIL_CMD };
120
121
122 /* This is a convenience macro for adding the identity of an SMTP command
123 to the circular buffer that holds a list of the last n received. */
124
125 #define HAD(n) \
126 smtp_connection_had[smtp_ch_index++] = n; \
127 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
128
129
130 /*************************************************
131 * Local static variables *
132 *************************************************/
133
134 static auth_instance *authenticated_by;
135 static BOOL auth_advertised;
136 #ifdef SUPPORT_TLS
137 static BOOL tls_advertised;
138 #endif
139 static BOOL dsn_advertised;
140 static BOOL esmtp;
141 static BOOL helo_required = FALSE;
142 static BOOL helo_verify = FALSE;
143 static BOOL helo_seen;
144 static BOOL helo_accept_junk;
145 static BOOL count_nonmail;
146 static BOOL pipelining_advertised;
147 static BOOL rcpt_smtp_response_same;
148 static BOOL rcpt_in_progress;
149 static int nonmail_command_count;
150 static BOOL smtp_exit_function_called = 0;
151 #ifdef SUPPORT_I18N
152 static BOOL smtputf8_advertised;
153 #endif
154 static int synprot_error_count;
155 static int unknown_command_count;
156 static int sync_cmd_limit;
157 static int smtp_write_error = 0;
158
159 static uschar *rcpt_smtp_response;
160 static uschar *smtp_data_buffer;
161 static uschar *smtp_cmd_data;
162
163 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
164 final fields of all except AUTH are forced TRUE at the start of a new message
165 setup, to allow one of each between messages that is not counted as a nonmail
166 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
167 allow a new EHLO after starting up TLS.
168
169 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
170 counted. However, the flag is changed when AUTH is received, so that multiple
171 failing AUTHs will eventually hit the limit. After a successful AUTH, another
172 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
173 forced TRUE, to allow for the re-authentication that can happen at that point.
174
175 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
176 count of non-mail commands and possibly provoke an error.
177
178 tls_auth is a pseudo-command, never expected in input. It is activated
179 on TLS startup and looks for a tls authenticator. */
180
181 static smtp_cmd_list cmd_list[] = {
182 /* name len cmd has_arg is_mail_cmd */
183
184 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
185 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
186 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
187 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
188 #ifdef SUPPORT_TLS
189 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
190 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, TRUE },
191 #endif
192
193 /* If you change anything above here, also fix the definitions below. */
194
195 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
196 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
197 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
198 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
199 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
200 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
201 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
202 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
203 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
204 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
205 };
206
207 static smtp_cmd_list *cmd_list_end =
208 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
209
210 #define CMD_LIST_RSET 0
211 #define CMD_LIST_HELO 1
212 #define CMD_LIST_EHLO 2
213 #define CMD_LIST_AUTH 3
214 #define CMD_LIST_STARTTLS 4
215 #define CMD_LIST_TLS_AUTH 5
216
217 /* This list of names is used for performing the smtp_no_mail logging action.
218 It must be kept in step with the SCH_xxx enumerations. */
219
220 static uschar *smtp_names[] =
221 {
222 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
223 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
224 US"STARTTLS", US"VRFY" };
225
226 static uschar *protocols_local[] = {
227 US"local-smtp", /* HELO */
228 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
229 US"local-esmtp", /* EHLO */
230 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
231 US"local-esmtpa", /* EHLO->AUTH */
232 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
233 };
234 static uschar *protocols[] = {
235 US"smtp", /* HELO */
236 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
237 US"esmtp", /* EHLO */
238 US"esmtps", /* EHLO->STARTTLS->EHLO */
239 US"esmtpa", /* EHLO->AUTH */
240 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
241 };
242
243 #define pnormal 0
244 #define pextend 2
245 #define pcrpted 1 /* added to pextend or pnormal */
246 #define pauthed 2 /* added to pextend */
247
248 /* Sanity check and validate optional args to MAIL FROM: envelope */
249 enum {
250 ENV_MAIL_OPT_NULL,
251 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
252 #ifndef DISABLE_PRDR
253 ENV_MAIL_OPT_PRDR,
254 #endif
255 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
256 #ifdef SUPPORT_I18N
257 ENV_MAIL_OPT_UTF8,
258 #endif
259 };
260 typedef struct {
261 uschar * name; /* option requested during MAIL cmd */
262 int value; /* enum type */
263 BOOL need_value; /* TRUE requires value (name=value pair format)
264 FALSE is a singleton */
265 } env_mail_type_t;
266 static env_mail_type_t env_mail_type_list[] = {
267 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
268 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
269 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
270 #ifndef DISABLE_PRDR
271 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
272 #endif
273 { US"RET", ENV_MAIL_OPT_RET, TRUE },
274 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
275 #ifdef SUPPORT_I18N
276 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
277 #endif
278 /* keep this the last entry */
279 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
280 };
281
282 /* When reading SMTP from a remote host, we have to use our own versions of the
283 C input-reading functions, in order to be able to flush the SMTP output only
284 when about to read more data from the socket. This is the only way to get
285 optimal performance when the client is using pipelining. Flushing for every
286 command causes a separate packet and reply packet each time; saving all the
287 responses up (when pipelining) combines them into one packet and one response.
288
289 For simplicity, these functions are used for *all* SMTP input, not only when
290 receiving over a socket. However, after setting up a secure socket (SSL), input
291 is read via the OpenSSL library, and another set of functions is used instead
292 (see tls.c).
293
294 These functions are set in the receive_getc etc. variables and called with the
295 same interface as the C functions. However, since there can only ever be
296 one incoming SMTP call, we just use a single buffer and flags. There is no need
297 to implement a complicated private FILE-like structure.*/
298
299 static uschar *smtp_inbuffer;
300 static uschar *smtp_inptr;
301 static uschar *smtp_inend;
302 static int smtp_had_eof;
303 static int smtp_had_error;
304
305
306 /* forward declarations */
307 static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
308 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
309 static void smtp_quit_handler(uschar **, uschar **);
310 static void smtp_rset_handler(void);
311
312 /*************************************************
313 * Recheck synchronization *
314 *************************************************/
315
316 /* Synchronization checks can never be perfect because a packet may be on its
317 way but not arrived when the check is done. Normally, the checks happen when
318 commands are read: Exim ensures that there is no more input in the input buffer.
319 In normal cases, the response to the command will be fast, and there is no
320 further check.
321
322 However, for some commands an ACL is run, and that can include delays. In those
323 cases, it is useful to do another check on the input just before sending the
324 response. This also applies at the start of a connection. This function does
325 that check by means of the select() function, as long as the facility is not
326 disabled or inappropriate. A failure of select() is ignored.
327
328 When there is unwanted input, we read it so that it appears in the log of the
329 error.
330
331 Arguments: none
332 Returns: TRUE if all is well; FALSE if there is input pending
333 */
334
335 static BOOL
336 wouldblock_reading(void)
337 {
338 int fd, rc;
339 fd_set fds;
340 struct timeval tzero;
341
342 if (tls_in.active >= 0)
343 return !tls_could_read();
344
345 if (smtp_inptr < smtp_inend)
346 return FALSE;
347
348 fd = fileno(smtp_in);
349 FD_ZERO(&fds);
350 FD_SET(fd, &fds);
351 tzero.tv_sec = 0;
352 tzero.tv_usec = 0;
353 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
354
355 if (rc <= 0) return TRUE; /* Not ready to read */
356 rc = smtp_getc(GETC_BUFFER_UNLIMITED);
357 if (rc < 0) return TRUE; /* End of file or error */
358
359 smtp_ungetc(rc);
360 rc = smtp_inend - smtp_inptr;
361 if (rc > 150) rc = 150;
362 smtp_inptr[rc] = 0;
363 return FALSE;
364 }
365
366 static BOOL
367 check_sync(void)
368 {
369 if (!smtp_enforce_sync || sender_host_address == NULL || sender_host_notsocket)
370 return TRUE;
371
372 return wouldblock_reading();
373 }
374
375
376 /* If there's input waiting (and we're doing pipelineing) then we can pipeline
377 a reponse with the one following. */
378
379 static BOOL
380 pipeline_response(void)
381 {
382 if ( !smtp_enforce_sync || !sender_host_address
383 || sender_host_notsocket || !pipelining_advertised)
384 return FALSE;
385
386 return !wouldblock_reading();
387 }
388
389
390
391 /*************************************************
392 * Log incomplete transactions *
393 *************************************************/
394
395 /* This function is called after a transaction has been aborted by RSET, QUIT,
396 connection drops or other errors. It logs the envelope information received
397 so far in order to preserve address verification attempts.
398
399 Argument: string to indicate what aborted the transaction
400 Returns: nothing
401 */
402
403 static void
404 incomplete_transaction_log(uschar *what)
405 {
406 if (sender_address == NULL || /* No transaction in progress */
407 !LOGGING(smtp_incomplete_transaction))
408 return;
409
410 /* Build list of recipients for logging */
411
412 if (recipients_count > 0)
413 {
414 int i;
415 raw_recipients = store_get(recipients_count * sizeof(uschar *));
416 for (i = 0; i < recipients_count; i++)
417 raw_recipients[i] = recipients_list[i].address;
418 raw_recipients_count = recipients_count;
419 }
420
421 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
422 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
423 }
424
425
426
427
428 /* Refill the buffer, and notify DKIM verification code.
429 Return false for error or EOF.
430 */
431
432 static BOOL
433 smtp_refill(unsigned lim)
434 {
435 int rc, save_errno;
436 if (!smtp_out) return FALSE;
437 fflush(smtp_out);
438 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
439
440 /* Limit amount read, so non-message data is not fed to DKIM */
441
442 rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE, lim));
443 save_errno = errno;
444 alarm(0);
445 if (rc <= 0)
446 {
447 /* Must put the error text in fixed store, because this might be during
448 header reading, where it releases unused store above the header. */
449 if (rc < 0)
450 {
451 smtp_had_error = save_errno;
452 smtp_read_error = string_copy_malloc(
453 string_sprintf(" (error: %s)", strerror(save_errno)));
454 }
455 else smtp_had_eof = 1;
456 return FALSE;
457 }
458 #ifndef DISABLE_DKIM
459 dkim_exim_verify_feed(smtp_inbuffer, rc);
460 #endif
461 smtp_inend = smtp_inbuffer + rc;
462 smtp_inptr = smtp_inbuffer;
463 return TRUE;
464 }
465
466 /*************************************************
467 * SMTP version of getc() *
468 *************************************************/
469
470 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
471 it flushes the output, and refills the buffer, with a timeout. The signal
472 handler is set appropriately by the calling function. This function is not used
473 after a connection has negotiated itself into an TLS/SSL state.
474
475 Arguments: lim Maximum amount to read/buffer
476 Returns: the next character or EOF
477 */
478
479 int
480 smtp_getc(unsigned lim)
481 {
482 if (smtp_inptr >= smtp_inend)
483 if (!smtp_refill(lim))
484 return EOF;
485 return *smtp_inptr++;
486 }
487
488 uschar *
489 smtp_getbuf(unsigned * len)
490 {
491 unsigned size;
492 uschar * buf;
493
494 if (smtp_inptr >= smtp_inend)
495 if (!smtp_refill(*len))
496 { *len = 0; return NULL; }
497
498 if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
499 buf = smtp_inptr;
500 smtp_inptr += size;
501 *len = size;
502 return buf;
503 }
504
505 void
506 smtp_get_cache(void)
507 {
508 #ifndef DISABLE_DKIM
509 int n = smtp_inend - smtp_inptr;
510 if (n > 0)
511 dkim_exim_verify_feed(smtp_inptr, n);
512 #endif
513 }
514
515
516 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
517 previous BDAT chunk and getting new ones when we run out. Uses the
518 underlying smtp_getc or tls_getc both for that and for getting the
519 (buffered) data byte. EOD signals (an expected) no further data.
520 ERR signals a protocol error, and EOF a closed input stream.
521
522 Called from read_bdat_smtp() in receive.c for the message body, but also
523 by the headers read loop in receive_msg(); manipulates chunking_state
524 to handle the BDAT command/response.
525 Placed here due to the correlation with the above smtp_getc(), which it wraps,
526 and also by the need to do smtp command/response handling.
527
528 Arguments: lim (ignored)
529 Returns: the next character or ERR, EOD or EOF
530 */
531
532 int
533 bdat_getc(unsigned lim)
534 {
535 uschar * user_msg = NULL;
536 uschar * log_msg;
537
538 for(;;)
539 {
540 #ifndef DISABLE_DKIM
541 BOOL dkim_save;
542 #endif
543
544 if (chunking_data_left > 0)
545 return lwr_receive_getc(chunking_data_left--);
546
547 receive_getc = lwr_receive_getc;
548 receive_getbuf = lwr_receive_getbuf;
549 receive_ungetc = lwr_receive_ungetc;
550 #ifndef DISABLE_DKIM
551 dkim_save = dkim_collect_input;
552 dkim_collect_input = FALSE;
553 #endif
554
555 /* Unless PIPELINING was offered, there should be no next command
556 until after we ack that chunk */
557
558 if (!pipelining_advertised && !check_sync())
559 {
560 unsigned n = smtp_inend - smtp_inptr;
561 if (n > 32) n = 32;
562
563 incomplete_transaction_log(US"sync failure");
564 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
565 "(next input sent too soon: pipelining was not advertised): "
566 "rejected \"%s\" %s next input=\"%s\"",
567 smtp_cmd_buffer, host_and_ident(TRUE),
568 string_printing(string_copyn(smtp_inptr, n)));
569 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
570 US"SMTP synchronization error");
571 goto repeat_until_rset;
572 }
573
574 /* If not the last, ack the received chunk. The last response is delayed
575 until after the data ACL decides on it */
576
577 if (chunking_state == CHUNKING_LAST)
578 {
579 #ifndef DISABLE_DKIM
580 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
581 #endif
582 return EOD;
583 }
584
585 smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize);
586 chunking_state = CHUNKING_OFFERED;
587 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
588
589 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
590 QUIT, RSET or NOOP but handling them seems obvious */
591
592 next_cmd:
593 switch(smtp_read_command(TRUE, 1))
594 {
595 default:
596 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
597 US"only BDAT permissible after non-LAST BDAT");
598
599 repeat_until_rset:
600 switch(smtp_read_command(TRUE, 1))
601 {
602 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
603 case EOF_CMD: return EOF;
604 case RSET_CMD: smtp_rset_handler(); return ERR;
605 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
606 US"only RSET accepted now") > 0)
607 return EOF;
608 goto repeat_until_rset;
609 }
610
611 case QUIT_CMD:
612 smtp_quit_handler(&user_msg, &log_msg);
613 /*FALLTHROUGH*/
614 case EOF_CMD:
615 return EOF;
616
617 case RSET_CMD:
618 smtp_rset_handler();
619 return ERR;
620
621 case NOOP_CMD:
622 HAD(SCH_NOOP);
623 smtp_printf("250 OK\r\n", FALSE);
624 goto next_cmd;
625
626 case BDAT_CMD:
627 {
628 int n;
629
630 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
631 {
632 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
633 US"missing size for BDAT command");
634 return ERR;
635 }
636 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
637 ? CHUNKING_LAST : CHUNKING_ACTIVE;
638 chunking_data_left = chunking_datasize;
639 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
640 (int)chunking_state, chunking_data_left);
641
642 if (chunking_datasize == 0)
643 if (chunking_state == CHUNKING_LAST)
644 return EOD;
645 else
646 {
647 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
648 US"zero size for BDAT command");
649 goto repeat_until_rset;
650 }
651
652 receive_getc = bdat_getc;
653 receive_getbuf = bdat_getbuf;
654 receive_ungetc = bdat_ungetc;
655 #ifndef DISABLE_DKIM
656 dkim_collect_input = dkim_save;
657 #endif
658 break; /* to top of main loop */
659 }
660 }
661 }
662 }
663
664 uschar *
665 bdat_getbuf(unsigned * len)
666 {
667 uschar * buf;
668
669 if (chunking_data_left <= 0)
670 { *len = 0; return NULL; }
671
672 if (*len > chunking_data_left) *len = chunking_data_left;
673 buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
674 chunking_data_left -= *len;
675 return buf;
676 }
677
678 void
679 bdat_flush_data(void)
680 {
681 unsigned n = chunking_data_left;
682 (void) bdat_getbuf(&n);
683
684 receive_getc = lwr_receive_getc;
685 receive_getbuf = lwr_receive_getbuf;
686 receive_ungetc = lwr_receive_ungetc;
687
688 if (chunking_state != CHUNKING_LAST)
689 {
690 chunking_state = CHUNKING_OFFERED;
691 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
692 }
693 }
694
695
696
697
698 /*************************************************
699 * SMTP version of ungetc() *
700 *************************************************/
701
702 /* Puts a character back in the input buffer. Only ever
703 called once.
704
705 Arguments:
706 ch the character
707
708 Returns: the character
709 */
710
711 int
712 smtp_ungetc(int ch)
713 {
714 *--smtp_inptr = ch;
715 return ch;
716 }
717
718
719 int
720 bdat_ungetc(int ch)
721 {
722 chunking_data_left++;
723 return lwr_receive_ungetc(ch);
724 }
725
726
727
728 /*************************************************
729 * SMTP version of feof() *
730 *************************************************/
731
732 /* Tests for a previous EOF
733
734 Arguments: none
735 Returns: non-zero if the eof flag is set
736 */
737
738 int
739 smtp_feof(void)
740 {
741 return smtp_had_eof;
742 }
743
744
745
746
747 /*************************************************
748 * SMTP version of ferror() *
749 *************************************************/
750
751 /* Tests for a previous read error, and returns with errno
752 restored to what it was when the error was detected.
753
754 Arguments: none
755 Returns: non-zero if the error flag is set
756 */
757
758 int
759 smtp_ferror(void)
760 {
761 errno = smtp_had_error;
762 return smtp_had_error;
763 }
764
765
766
767 /*************************************************
768 * Test for characters in the SMTP buffer *
769 *************************************************/
770
771 /* Used at the end of a message
772
773 Arguments: none
774 Returns: TRUE/FALSE
775 */
776
777 BOOL
778 smtp_buffered(void)
779 {
780 return smtp_inptr < smtp_inend;
781 }
782
783
784
785 /*************************************************
786 * Write formatted string to SMTP channel *
787 *************************************************/
788
789 /* This is a separate function so that we don't have to repeat everything for
790 TLS support or debugging. It is global so that the daemon and the
791 authentication functions can use it. It does not return any error indication,
792 because major problems such as dropped connections won't show up till an output
793 flush for non-TLS connections. The smtp_fflush() function is available for
794 checking that: for convenience, TLS output errors are remembered here so that
795 they are also picked up later by smtp_fflush().
796
797 Arguments:
798 format format string
799 more further data expected
800 ... optional arguments
801
802 Returns: nothing
803 */
804
805 void
806 smtp_printf(const char *format, BOOL more, ...)
807 {
808 va_list ap;
809
810 va_start(ap, more);
811 smtp_vprintf(format, more, ap);
812 va_end(ap);
813 }
814
815 /* This is split off so that verify.c:respond_printf() can, in effect, call
816 smtp_printf(), bearing in mind that in C a vararg function can't directly
817 call another vararg function, only a function which accepts a va_list. */
818
819 void
820 smtp_vprintf(const char *format, BOOL more, va_list ap)
821 {
822 BOOL yield;
823
824 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
825
826 DEBUG(D_receive)
827 {
828 void *reset_point = store_get(0);
829 uschar *msg_copy, *cr, *end;
830 msg_copy = string_copy(big_buffer);
831 end = msg_copy + Ustrlen(msg_copy);
832 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
833 memmove(cr, cr + 1, (end--) - cr);
834 debug_printf("SMTP>> %s", msg_copy);
835 store_reset(reset_point);
836 }
837
838 if (!yield)
839 {
840 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
841 smtp_closedown(US"Unexpected error");
842 exim_exit(EXIT_FAILURE);
843 }
844
845 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
846 have had the same. Note: this code is also present in smtp_respond(). It would
847 be tidier to have it only in one place, but when it was added, it was easier to
848 do it that way, so as not to have to mess with the code for the RCPT command,
849 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
850
851 if (rcpt_in_progress)
852 {
853 if (rcpt_smtp_response == NULL)
854 rcpt_smtp_response = string_copy(big_buffer);
855 else if (rcpt_smtp_response_same &&
856 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
857 rcpt_smtp_response_same = FALSE;
858 rcpt_in_progress = FALSE;
859 }
860
861 /* Now write the string */
862
863 #ifdef SUPPORT_TLS
864 if (tls_in.active >= 0)
865 {
866 if (tls_write(TRUE, big_buffer, Ustrlen(big_buffer), more) < 0)
867 smtp_write_error = -1;
868 }
869 else
870 #endif
871
872 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
873 }
874
875
876
877 /*************************************************
878 * Flush SMTP out and check for error *
879 *************************************************/
880
881 /* This function isn't currently used within Exim (it detects errors when it
882 tries to read the next SMTP input), but is available for use in local_scan().
883 For non-TLS connections, it flushes the output and checks for errors. For
884 TLS-connections, it checks for a previously-detected TLS write error.
885
886 Arguments: none
887 Returns: 0 for no error; -1 after an error
888 */
889
890 int
891 smtp_fflush(void)
892 {
893 if (tls_in.active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
894 return smtp_write_error;
895 }
896
897
898
899 /*************************************************
900 * SMTP command read timeout *
901 *************************************************/
902
903 /* Signal handler for timing out incoming SMTP commands. This attempts to
904 finish off tidily.
905
906 Argument: signal number (SIGALRM)
907 Returns: nothing
908 */
909
910 static void
911 command_timeout_handler(int sig)
912 {
913 sig = sig; /* Keep picky compilers happy */
914 log_write(L_lost_incoming_connection,
915 LOG_MAIN, "SMTP command timeout on%s connection from %s",
916 (tls_in.active >= 0)? " TLS" : "",
917 host_and_ident(FALSE));
918 if (smtp_batched_input)
919 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
920 smtp_notquit_exit(US"command-timeout", US"421",
921 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
922 exim_exit(EXIT_FAILURE);
923 }
924
925
926
927 /*************************************************
928 * SIGTERM received *
929 *************************************************/
930
931 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
932
933 Argument: signal number (SIGTERM)
934 Returns: nothing
935 */
936
937 static void
938 command_sigterm_handler(int sig)
939 {
940 sig = sig; /* Keep picky compilers happy */
941 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
942 if (smtp_batched_input)
943 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
944 smtp_notquit_exit(US"signal-exit", US"421",
945 US"%s: Service not available - closing connection", smtp_active_hostname);
946 exim_exit(EXIT_FAILURE);
947 }
948
949
950
951
952 #ifdef SUPPORT_PROXY
953 /*************************************************
954 * Restore socket timeout to previous value *
955 *************************************************/
956 /* If the previous value was successfully retrieved, restore
957 it before returning control to the non-proxy routines
958
959 Arguments: fd - File descriptor for input
960 get_ok - Successfully retrieved previous values
961 tvtmp - Time struct with previous values
962 vslen - Length of time struct
963 Returns: none
964 */
965 static void
966 restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
967 {
968 if (get_ok == 0)
969 (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
970 }
971
972 /*************************************************
973 * Check if host is required proxy host *
974 *************************************************/
975 /* The function determines if inbound host will be a regular smtp host
976 or if it is configured that it must use Proxy Protocol. A local
977 connection cannot.
978
979 Arguments: none
980 Returns: bool
981 */
982
983 static BOOL
984 check_proxy_protocol_host()
985 {
986 int rc;
987
988 if ( sender_host_address
989 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
990 sender_host_address, NULL)) == OK)
991 {
992 DEBUG(D_receive)
993 debug_printf("Detected proxy protocol configured host\n");
994 proxy_session = TRUE;
995 }
996 return proxy_session;
997 }
998
999
1000 /*************************************************
1001 * Read data until newline or end of buffer *
1002 *************************************************/
1003 /* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
1004 read an entire buffer and assume there will be nothing past a proxy protocol
1005 header. Our approach normally is to use stdio, but again that relies upon
1006 "STARTTLS\r\n" and a server response before the client starts TLS handshake, or
1007 reading _nothing_ before client TLS handshake. So we don't want to use the
1008 usual buffering reads which may read enough to block TLS starting.
1009
1010 So unfortunately we're down to "read one byte at a time, with a syscall each,
1011 and expect a little overhead", for all proxy-opened connections which are v1,
1012 just to handle the TLS-on-connect case. Since SSL functions wrap the
1013 underlying fd, we can't assume that we can feed them any already-read content.
1014
1015 We need to know where to read to, the max capacity, and we'll read until we
1016 get a CR and one more character. Let the caller scream if it's CR+!LF.
1017
1018 Return the amount read.
1019 */
1020
1021 static int
1022 swallow_until_crlf(int fd, uschar *base, int already, int capacity)
1023 {
1024 uschar *to = base + already;
1025 uschar *cr;
1026 int have = 0;
1027 int ret;
1028 int last = 0;
1029
1030 /* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1031 up through the \r; for the _normal_ case, we haven't yet seen the \r. */
1032
1033 cr = memchr(base, '\r', already);
1034 if (cr != NULL)
1035 {
1036 if ((cr - base) < already - 1)
1037 {
1038 /* \r and presumed \n already within what we have; probably not
1039 actually proxy protocol, but abort cleanly. */
1040 return 0;
1041 }
1042 /* \r is last character read, just need one more. */
1043 last = 1;
1044 }
1045
1046 while (capacity > 0)
1047 {
1048 do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR);
1049 if (ret == -1)
1050 return -1;
1051 have++;
1052 if (last)
1053 return have;
1054 if (*to == '\r')
1055 last = 1;
1056 capacity--;
1057 to++;
1058 }
1059
1060 /* reached end without having room for a final newline, abort */
1061 errno = EOVERFLOW;
1062 return -1;
1063 }
1064
1065 /*************************************************
1066 * Setup host for proxy protocol *
1067 *************************************************/
1068 /* The function configures the connection based on a header from the
1069 inbound host to use Proxy Protocol. The specification is very exact
1070 so exit with an error if do not find the exact required pieces. This
1071 includes an incorrect number of spaces separating args.
1072
1073 Arguments: none
1074 Returns: Boolean success
1075 */
1076
1077 static void
1078 setup_proxy_protocol_host()
1079 {
1080 union {
1081 struct {
1082 uschar line[108];
1083 } v1;
1084 struct {
1085 uschar sig[12];
1086 uint8_t ver_cmd;
1087 uint8_t fam;
1088 uint16_t len;
1089 union {
1090 struct { /* TCP/UDP over IPv4, len = 12 */
1091 uint32_t src_addr;
1092 uint32_t dst_addr;
1093 uint16_t src_port;
1094 uint16_t dst_port;
1095 } ip4;
1096 struct { /* TCP/UDP over IPv6, len = 36 */
1097 uint8_t src_addr[16];
1098 uint8_t dst_addr[16];
1099 uint16_t src_port;
1100 uint16_t dst_port;
1101 } ip6;
1102 struct { /* AF_UNIX sockets, len = 216 */
1103 uschar src_addr[108];
1104 uschar dst_addr[108];
1105 } unx;
1106 } addr;
1107 } v2;
1108 } hdr;
1109
1110 /* Temp variables used in PPv2 address:port parsing */
1111 uint16_t tmpport;
1112 char tmpip[INET_ADDRSTRLEN];
1113 struct sockaddr_in tmpaddr;
1114 char tmpip6[INET6_ADDRSTRLEN];
1115 struct sockaddr_in6 tmpaddr6;
1116
1117 /* We can't read "all data until end" because while SMTP is
1118 server-speaks-first, the TLS handshake is client-speaks-first, so for
1119 TLS-on-connect ports the proxy protocol header will usually be immediately
1120 followed by a TLS handshake, and with N TLS libraries, we can't reliably
1121 reinject data for reading by those. So instead we first read "enough to be
1122 safely read within the header, and figure out how much more to read".
1123 For v1 we will later read to the end-of-line, for v2 we will read based upon
1124 the stated length.
1125
1126 The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1127 data is needed total. For v1, where the line looks like:
1128 PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1129
1130 However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1131 We seem to support that. So, if we read 14 octets then we can tell if we're
1132 v2 or v1. If we're v1, we can continue reading as normal.
1133
1134 If we're v2, we can't slurp up the entire header. We need the length in the
1135 15th & 16th octets, then to read everything after that.
1136
1137 So to safely handle v1 and v2, with client-sent-first supported correctly,
1138 we have to do a minimum of 3 read calls, not 1. Eww.
1139 */
1140
1141 #define PROXY_INITIAL_READ 14
1142 #define PROXY_V2_HEADER_SIZE 16
1143 #if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1144 # error Code bug in sizes of data to read for proxy usage
1145 #endif
1146
1147 int get_ok = 0;
1148 int size, ret;
1149 int fd = fileno(smtp_in);
1150 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
1151 uschar * iptype; /* To display debug info */
1152 struct timeval tv;
1153 struct timeval tvtmp;
1154 socklen_t vslen = sizeof(struct timeval);
1155 BOOL yield = FALSE;
1156
1157 /* Save current socket timeout values */
1158 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
1159
1160 /* Proxy Protocol host must send header within a short time
1161 (default 3 seconds) or it's considered invalid */
1162 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
1163 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
1164 if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
1165 goto bad;
1166
1167 do
1168 {
1169 /* The inbound host was declared to be a Proxy Protocol host, so
1170 don't do a PEEK into the data, actually slurp up enough to be
1171 "safe". Can't take it all because TLS-on-connect clients follow
1172 immediately with TLS handshake. */
1173 ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0);
1174 }
1175 while (ret == -1 && errno == EINTR);
1176
1177 if (ret == -1)
1178 goto proxyfail;
1179
1180 /* For v2, handle reading the length, and then the rest. */
1181 if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
1182 {
1183 int retmore;
1184 uint8_t ver;
1185
1186 /* First get the length fields. */
1187 do
1188 {
1189 retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0);
1190 } while (retmore == -1 && errno == EINTR);
1191 if (retmore == -1)
1192 goto proxyfail;
1193 ret += retmore;
1194
1195 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
1196
1197 /* May 2014: haproxy combined the version and command into one byte to
1198 allow two full bytes for the length field in order to proxy SSL
1199 connections. SSL Proxy is not supported in this version of Exim, but
1200 must still separate values here. */
1201
1202 if (ver != 0x02)
1203 {
1204 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1205 goto proxyfail;
1206 }
1207
1208 /* The v2 header will always be 16 bytes per the spec. */
1209 size = 16 + ntohs(hdr.v2.len);
1210 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1211 size, (int)sizeof(hdr));
1212
1213 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1214 amount that we need. Double-check that the size is not unreasonable, then
1215 get the rest. */
1216 if (size > sizeof(hdr))
1217 {
1218 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
1219 goto proxyfail;
1220 }
1221
1222 do
1223 {
1224 do
1225 {
1226 retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0);
1227 } while (retmore == -1 && errno == EINTR);
1228 if (retmore == -1)
1229 goto proxyfail;
1230 ret += retmore;
1231 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1232 } while (ret < size);
1233
1234 } /* end scope for getting rest of data for v2 */
1235
1236 /* At this point: if PROXYv2, we've read the exact size required for all data;
1237 if PROXYv1 then we've read "less than required for any valid line" and should
1238 read the rest". */
1239
1240 if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1241 {
1242 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1243
1244 switch (cmd)
1245 {
1246 case 0x01: /* PROXY command */
1247 switch (hdr.v2.fam)
1248 {
1249 case 0x11: /* TCPv4 address type */
1250 iptype = US"IPv4";
1251 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
1252 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1253 if (!string_is_ip_address(US tmpip, NULL))
1254 {
1255 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1256 goto proxyfail;
1257 }
1258 proxy_local_address = sender_host_address;
1259 sender_host_address = string_copy(US tmpip);
1260 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
1261 proxy_local_port = sender_host_port;
1262 sender_host_port = tmpport;
1263 /* Save dest ip/port */
1264 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
1265 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1266 if (!string_is_ip_address(US tmpip, NULL))
1267 {
1268 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1269 goto proxyfail;
1270 }
1271 proxy_external_address = string_copy(US tmpip);
1272 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
1273 proxy_external_port = tmpport;
1274 goto done;
1275 case 0x21: /* TCPv6 address type */
1276 iptype = US"IPv6";
1277 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
1278 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1279 if (!string_is_ip_address(US tmpip6, NULL))
1280 {
1281 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
1282 goto proxyfail;
1283 }
1284 proxy_local_address = sender_host_address;
1285 sender_host_address = string_copy(US tmpip6);
1286 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
1287 proxy_local_port = sender_host_port;
1288 sender_host_port = tmpport;
1289 /* Save dest ip/port */
1290 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
1291 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1292 if (!string_is_ip_address(US tmpip6, NULL))
1293 {
1294 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
1295 goto proxyfail;
1296 }
1297 proxy_external_address = string_copy(US tmpip6);
1298 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
1299 proxy_external_port = tmpport;
1300 goto done;
1301 default:
1302 DEBUG(D_receive)
1303 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1304 hdr.v2.fam);
1305 goto proxyfail;
1306 }
1307 /* Unsupported protocol, keep local connection address */
1308 break;
1309 case 0x00: /* LOCAL command */
1310 /* Keep local connection address for LOCAL */
1311 iptype = US"local";
1312 break;
1313 default:
1314 DEBUG(D_receive)
1315 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
1316 goto proxyfail;
1317 }
1318 }
1319 else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
1320 {
1321 uschar *p;
1322 uschar *end;
1323 uschar *sp; /* Utility variables follow */
1324 int tmp_port;
1325 int r2;
1326 char *endc;
1327
1328 /* get the rest of the line */
1329 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1330 if (r2 == -1)
1331 goto proxyfail;
1332 ret += r2;
1333
1334 p = string_copy(hdr.v1.line);
1335 end = memchr(p, '\r', ret - 1);
1336
1337 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
1338 {
1339 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1340 goto proxyfail;
1341 }
1342 *end = '\0'; /* Terminate the string */
1343 size = end + 2 - p; /* Skip header + CRLF */
1344 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
1345 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
1346 /* Step through the string looking for the required fields. Ensure
1347 strict adherence to required formatting, exit for any error. */
1348 p += 5;
1349 if (!isspace(*(p++)))
1350 {
1351 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1352 goto proxyfail;
1353 }
1354 if (!Ustrncmp(p, CCS"TCP4", 4))
1355 iptype = US"IPv4";
1356 else if (!Ustrncmp(p,CCS"TCP6", 4))
1357 iptype = US"IPv6";
1358 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1359 {
1360 iptype = US"Unknown";
1361 goto done;
1362 }
1363 else
1364 {
1365 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1366 goto proxyfail;
1367 }
1368
1369 p += Ustrlen(iptype);
1370 if (!isspace(*(p++)))
1371 {
1372 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1373 goto proxyfail;
1374 }
1375 /* Find the end of the arg */
1376 if ((sp = Ustrchr(p, ' ')) == NULL)
1377 {
1378 DEBUG(D_receive)
1379 debug_printf("Did not find proxied src %s\n", iptype);
1380 goto proxyfail;
1381 }
1382 *sp = '\0';
1383 if(!string_is_ip_address(p, NULL))
1384 {
1385 DEBUG(D_receive)
1386 debug_printf("Proxied src arg is not an %s address\n", iptype);
1387 goto proxyfail;
1388 }
1389 proxy_local_address = sender_host_address;
1390 sender_host_address = p;
1391 p = sp + 1;
1392 if ((sp = Ustrchr(p, ' ')) == NULL)
1393 {
1394 DEBUG(D_receive)
1395 debug_printf("Did not find proxy dest %s\n", iptype);
1396 goto proxyfail;
1397 }
1398 *sp = '\0';
1399 if(!string_is_ip_address(p, NULL))
1400 {
1401 DEBUG(D_receive)
1402 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1403 goto proxyfail;
1404 }
1405 proxy_external_address = p;
1406 p = sp + 1;
1407 if ((sp = Ustrchr(p, ' ')) == NULL)
1408 {
1409 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1410 goto proxyfail;
1411 }
1412 *sp = '\0';
1413 tmp_port = strtol(CCS p, &endc, 10);
1414 if (*endc || tmp_port == 0)
1415 {
1416 DEBUG(D_receive)
1417 debug_printf("Proxied src port '%s' not an integer\n", p);
1418 goto proxyfail;
1419 }
1420 proxy_local_port = sender_host_port;
1421 sender_host_port = tmp_port;
1422 p = sp + 1;
1423 if ((sp = Ustrchr(p, '\0')) == NULL)
1424 {
1425 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1426 goto proxyfail;
1427 }
1428 tmp_port = strtol(CCS p, &endc, 10);
1429 if (*endc || tmp_port == 0)
1430 {
1431 DEBUG(D_receive)
1432 debug_printf("Proxy dest port '%s' not an integer\n", p);
1433 goto proxyfail;
1434 }
1435 proxy_external_port = tmp_port;
1436 /* Already checked for /r /n above. Good V1 header received. */
1437 }
1438 else
1439 {
1440 /* Wrong protocol */
1441 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1442 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
1443 goto proxyfail;
1444 }
1445
1446 done:
1447 DEBUG(D_receive)
1448 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1449 yield = proxy_session;
1450
1451 /* Don't flush any potential buffer contents. Any input on proxyfail
1452 should cause a synchronization failure */
1453
1454 proxyfail:
1455 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1456
1457 bad:
1458 if (yield)
1459 {
1460 sender_host_name = NULL;
1461 (void) host_name_lookup();
1462 host_build_sender_fullhost();
1463 }
1464 else
1465 {
1466 proxy_session_failed = TRUE;
1467 DEBUG(D_receive)
1468 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1469 }
1470
1471 return;
1472 }
1473 #endif
1474
1475 /*************************************************
1476 * Read one command line *
1477 *************************************************/
1478
1479 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1480 There are sites that don't do this, and in any case internal SMTP probably
1481 should check only for LF. Consequently, we check here for LF only. The line
1482 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1483 an unknown command. The command is read into the global smtp_cmd_buffer so that
1484 it is available via $smtp_command.
1485
1486 The character reading routine sets up a timeout for each block actually read
1487 from the input (which may contain more than one command). We set up a special
1488 signal handler that closes down the session on a timeout. Control does not
1489 return when it runs.
1490
1491 Arguments:
1492 check_sync if TRUE, check synchronization rules if global option is TRUE
1493 buffer_lim maximum to buffer in lower layer
1494
1495 Returns: a code identifying the command (enumerated above)
1496 */
1497
1498 static int
1499 smtp_read_command(BOOL check_sync, unsigned buffer_lim)
1500 {
1501 int c;
1502 int ptr = 0;
1503 smtp_cmd_list *p;
1504 BOOL hadnull = FALSE;
1505
1506 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1507
1508 while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
1509 {
1510 if (ptr >= SMTP_CMD_BUFFER_SIZE)
1511 {
1512 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1513 return OTHER_CMD;
1514 }
1515 if (c == 0)
1516 {
1517 hadnull = TRUE;
1518 c = '?';
1519 }
1520 smtp_cmd_buffer[ptr++] = c;
1521 }
1522
1523 receive_linecount++; /* For BSMTP errors */
1524 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1525
1526 /* If hit end of file, return pseudo EOF command. Whether we have a
1527 part-line already read doesn't matter, since this is an error state. */
1528
1529 if (c == EOF) return EOF_CMD;
1530
1531 /* Remove any CR and white space at the end of the line, and terminate the
1532 string. */
1533
1534 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1535 smtp_cmd_buffer[ptr] = 0;
1536
1537 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1538
1539 /* NULLs are not allowed in SMTP commands */
1540
1541 if (hadnull) return BADCHAR_CMD;
1542
1543 /* Scan command list and return identity, having set the data pointer
1544 to the start of the actual data characters. Check for SMTP synchronization
1545 if required. */
1546
1547 for (p = cmd_list; p < cmd_list_end; p++)
1548 {
1549 #ifdef SUPPORT_PROXY
1550 /* Only allow QUIT command if Proxy Protocol parsing failed */
1551 if (proxy_session && proxy_session_failed && p->cmd != QUIT_CMD)
1552 continue;
1553 #endif
1554 if ( p->len
1555 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1556 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1557 || smtp_cmd_buffer[p->len] == 0
1558 || smtp_cmd_buffer[p->len] == ' '
1559 ) )
1560 {
1561 if (smtp_inptr < smtp_inend && /* Outstanding input */
1562 p->cmd < sync_cmd_limit && /* Command should sync */
1563 check_sync && /* Local flag set */
1564 smtp_enforce_sync && /* Global flag set */
1565 sender_host_address != NULL && /* Not local input */
1566 !sender_host_notsocket) /* Really is a socket */
1567 return BADSYN_CMD;
1568
1569 /* The variables $smtp_command and $smtp_command_argument point into the
1570 unmodified input buffer. A copy of the latter is taken for actual
1571 processing, so that it can be chopped up into separate parts if necessary,
1572 for example, when processing a MAIL command options such as SIZE that can
1573 follow the sender address. */
1574
1575 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1576 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1577 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1578 smtp_cmd_data = smtp_data_buffer;
1579
1580 /* Count non-mail commands from those hosts that are controlled in this
1581 way. The default is all hosts. We don't waste effort checking the list
1582 until we get a non-mail command, but then cache the result to save checking
1583 again. If there's a DEFER while checking the host, assume it's in the list.
1584
1585 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1586 start of each incoming message by fiddling with the value in the table. */
1587
1588 if (!p->is_mail_cmd)
1589 {
1590 if (count_nonmail == TRUE_UNSET) count_nonmail =
1591 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1592 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1593 return TOO_MANY_NONMAIL_CMD;
1594 }
1595
1596 /* If there is data for a command that does not expect it, generate the
1597 error here. */
1598
1599 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1600 }
1601 }
1602
1603 #ifdef SUPPORT_PROXY
1604 /* Only allow QUIT command if Proxy Protocol parsing failed */
1605 if (proxy_session && proxy_session_failed)
1606 return PROXY_FAIL_IGNORE_CMD;
1607 #endif
1608
1609 /* Enforce synchronization for unknown commands */
1610
1611 if (smtp_inptr < smtp_inend && /* Outstanding input */
1612 check_sync && /* Local flag set */
1613 smtp_enforce_sync && /* Global flag set */
1614 sender_host_address != NULL && /* Not local input */
1615 !sender_host_notsocket) /* Really is a socket */
1616 return BADSYN_CMD;
1617
1618 return OTHER_CMD;
1619 }
1620
1621
1622
1623 /*************************************************
1624 * Forced closedown of call *
1625 *************************************************/
1626
1627 /* This function is called from log.c when Exim is dying because of a serious
1628 disaster, and also from some other places. If an incoming non-batched SMTP
1629 channel is open, it swallows the rest of the incoming message if in the DATA
1630 phase, sends the reply string, and gives an error to all subsequent commands
1631 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1632 smtp_in.
1633
1634 Arguments:
1635 message SMTP reply string to send, excluding the code
1636
1637 Returns: nothing
1638 */
1639
1640 void
1641 smtp_closedown(uschar *message)
1642 {
1643 if (smtp_in == NULL || smtp_batched_input) return;
1644 receive_swallow_smtp();
1645 smtp_printf("421 %s\r\n", FALSE, message);
1646
1647 for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
1648 {
1649 case EOF_CMD:
1650 return;
1651
1652 case QUIT_CMD:
1653 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
1654 mac_smtp_fflush();
1655 return;
1656
1657 case RSET_CMD:
1658 smtp_printf("250 Reset OK\r\n", FALSE);
1659 break;
1660
1661 default:
1662 smtp_printf("421 %s\r\n", FALSE, message);
1663 break;
1664 }
1665 }
1666
1667
1668
1669
1670 /*************************************************
1671 * Set up connection info for logging *
1672 *************************************************/
1673
1674 /* This function is called when logging information about an SMTP connection.
1675 It sets up appropriate source information, depending on the type of connection.
1676 If sender_fullhost is NULL, we are at a very early stage of the connection;
1677 just use the IP address.
1678
1679 Argument: none
1680 Returns: a string describing the connection
1681 */
1682
1683 uschar *
1684 smtp_get_connection_info(void)
1685 {
1686 const uschar * hostname = sender_fullhost
1687 ? sender_fullhost : sender_host_address;
1688
1689 if (host_checking)
1690 return string_sprintf("SMTP connection from %s", hostname);
1691
1692 if (sender_host_unknown || sender_host_notsocket)
1693 return string_sprintf("SMTP connection from %s", sender_ident);
1694
1695 if (is_inetd)
1696 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1697
1698 if (LOGGING(incoming_interface) && interface_address != NULL)
1699 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1700 interface_address, interface_port);
1701
1702 return string_sprintf("SMTP connection from %s", hostname);
1703 }
1704
1705
1706
1707 #ifdef SUPPORT_TLS
1708 /* Append TLS-related information to a log line
1709
1710 Arguments:
1711 s String under construction: allocated string to extend, or NULL
1712 sizep Pointer to current allocation size (update on return), or NULL
1713 ptrp Pointer to index for new entries in string (update on return), or NULL
1714
1715 Returns: Allocated string or NULL
1716 */
1717 static uschar *
1718 s_tlslog(uschar * s, int * sizep, int * ptrp)
1719 {
1720 int size = sizep ? *sizep : 0;
1721 int ptr = ptrp ? *ptrp : 0;
1722
1723 if (LOGGING(tls_cipher) && tls_in.cipher != NULL)
1724 s = string_append(s, &size, &ptr, 2, US" X=", tls_in.cipher);
1725 if (LOGGING(tls_certificate_verified) && tls_in.cipher != NULL)
1726 s = string_append(s, &size, &ptr, 2, US" CV=",
1727 tls_in.certificate_verified? "yes":"no");
1728 if (LOGGING(tls_peerdn) && tls_in.peerdn != NULL)
1729 s = string_append(s, &size, &ptr, 3, US" DN=\"",
1730 string_printing(tls_in.peerdn), US"\"");
1731 if (LOGGING(tls_sni) && tls_in.sni != NULL)
1732 s = string_append(s, &size, &ptr, 3, US" SNI=\"",
1733 string_printing(tls_in.sni), US"\"");
1734
1735 if (s)
1736 {
1737 s[ptr] = '\0';
1738 if (sizep) *sizep = size;
1739 if (ptrp) *ptrp = ptr;
1740 }
1741 return s;
1742 }
1743 #endif
1744
1745 /*************************************************
1746 * Log lack of MAIL if so configured *
1747 *************************************************/
1748
1749 /* This function is called when an SMTP session ends. If the log selector
1750 smtp_no_mail is set, write a log line giving some details of what has happened
1751 in the SMTP session.
1752
1753 Arguments: none
1754 Returns: nothing
1755 */
1756
1757 void
1758 smtp_log_no_mail(void)
1759 {
1760 int size, ptr, i;
1761 uschar *s, *sep;
1762
1763 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1764 return;
1765
1766 s = NULL;
1767 size = ptr = 0;
1768
1769 if (sender_host_authenticated != NULL)
1770 {
1771 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
1772 if (authenticated_id != NULL)
1773 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
1774 }
1775
1776 #ifdef SUPPORT_TLS
1777 s = s_tlslog(s, &size, &ptr);
1778 #endif
1779
1780 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
1781 US" C=..." : US" C=";
1782 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1783 {
1784 if (smtp_connection_had[i] != SCH_NONE)
1785 {
1786 s = string_append(s, &size, &ptr, 2, sep,
1787 smtp_names[smtp_connection_had[i]]);
1788 sep = US",";
1789 }
1790 }
1791
1792 for (i = 0; i < smtp_ch_index; i++)
1793 {
1794 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
1795 sep = US",";
1796 }
1797
1798 if (s != NULL) s[ptr] = 0; else s = US"";
1799 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
1800 host_and_ident(FALSE),
1801 readconf_printtime( (int) ((long)time(NULL) - (long)smtp_connection_start)),
1802 s);
1803 }
1804
1805
1806
1807 /*************************************************
1808 * Check HELO line and set sender_helo_name *
1809 *************************************************/
1810
1811 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1812 the domain name of the sending host, or an ip literal in square brackets. The
1813 argument is placed in sender_helo_name, which is in malloc store, because it
1814 must persist over multiple incoming messages. If helo_accept_junk is set, this
1815 host is permitted to send any old junk (needed for some broken hosts).
1816 Otherwise, helo_allow_chars can be used for rogue characters in general
1817 (typically people want to let in underscores).
1818
1819 Argument:
1820 s the data portion of the line (already past any white space)
1821
1822 Returns: TRUE or FALSE
1823 */
1824
1825 static BOOL
1826 check_helo(uschar *s)
1827 {
1828 uschar *start = s;
1829 uschar *end = s + Ustrlen(s);
1830 BOOL yield = helo_accept_junk;
1831
1832 /* Discard any previous helo name */
1833
1834 if (sender_helo_name != NULL)
1835 {
1836 store_free(sender_helo_name);
1837 sender_helo_name = NULL;
1838 }
1839
1840 /* Skip tests if junk is permitted. */
1841
1842 if (!yield)
1843 {
1844 /* Allow the new standard form for IPv6 address literals, namely,
1845 [IPv6:....], and because someone is bound to use it, allow an equivalent
1846 IPv4 form. Allow plain addresses as well. */
1847
1848 if (*s == '[')
1849 {
1850 if (end[-1] == ']')
1851 {
1852 end[-1] = 0;
1853 if (strncmpic(s, US"[IPv6:", 6) == 0)
1854 yield = (string_is_ip_address(s+6, NULL) == 6);
1855 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1856 yield = (string_is_ip_address(s+6, NULL) == 4);
1857 else
1858 yield = (string_is_ip_address(s+1, NULL) != 0);
1859 end[-1] = ']';
1860 }
1861 }
1862
1863 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1864 that have been configured (usually underscore - sigh). */
1865
1866 else if (*s != 0)
1867 {
1868 yield = TRUE;
1869 while (*s != 0)
1870 {
1871 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1872 Ustrchr(helo_allow_chars, *s) == NULL)
1873 {
1874 yield = FALSE;
1875 break;
1876 }
1877 s++;
1878 }
1879 }
1880 }
1881
1882 /* Save argument if OK */
1883
1884 if (yield) sender_helo_name = string_copy_malloc(start);
1885 return yield;
1886 }
1887
1888
1889
1890
1891
1892 /*************************************************
1893 * Extract SMTP command option *
1894 *************************************************/
1895
1896 /* This function picks the next option setting off the end of smtp_cmd_data. It
1897 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1898 things that can appear there.
1899
1900 Arguments:
1901 name point this at the name
1902 value point this at the data string
1903
1904 Returns: TRUE if found an option
1905 */
1906
1907 static BOOL
1908 extract_option(uschar **name, uschar **value)
1909 {
1910 uschar *n;
1911 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1912 while (isspace(*v)) v--;
1913 v[1] = 0;
1914 while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1915 {
1916 /* Take care to not stop at a space embedded in a quoted local-part */
1917
1918 if (*v == '"') do v--; while (*v != '"' && v > smtp_cmd_data+1);
1919 v--;
1920 }
1921
1922 n = v;
1923 if (*v == '=')
1924 {
1925 while(isalpha(n[-1])) n--;
1926 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1927 if (!isspace(n[-1])) return FALSE;
1928 n[-1] = 0;
1929 }
1930 else
1931 {
1932 n++;
1933 if (v == smtp_cmd_data) return FALSE;
1934 }
1935 *v++ = 0;
1936 *name = n;
1937 *value = v;
1938 return TRUE;
1939 }
1940
1941
1942
1943
1944
1945 /*************************************************
1946 * Reset for new message *
1947 *************************************************/
1948
1949 /* This function is called whenever the SMTP session is reset from
1950 within either of the setup functions.
1951
1952 Argument: the stacking pool storage reset point
1953 Returns: nothing
1954 */
1955
1956 static void
1957 smtp_reset(void *reset_point)
1958 {
1959 recipients_list = NULL;
1960 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1961 raw_recipients_count = recipients_count = recipients_list_max = 0;
1962 message_linecount = 0;
1963 message_size = -1;
1964 acl_added_headers = NULL;
1965 acl_removed_headers = NULL;
1966 queue_only_policy = FALSE;
1967 rcpt_smtp_response = NULL;
1968 rcpt_smtp_response_same = TRUE;
1969 rcpt_in_progress = FALSE;
1970 deliver_freeze = FALSE; /* Can be set by ACL */
1971 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1972 fake_response = OK; /* Can be set by ACL */
1973 #ifdef WITH_CONTENT_SCAN
1974 no_mbox_unspool = FALSE; /* Can be set by ACL */
1975 #endif
1976 submission_mode = FALSE; /* Can be set by ACL */
1977 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
1978 active_local_from_check = local_from_check; /* Can be set by ACL */
1979 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1980 sending_ip_address = NULL;
1981 return_path = sender_address = NULL;
1982 sender_data = NULL; /* Can be set by ACL */
1983 deliver_localpart_orig = NULL;
1984 deliver_domain_orig = NULL;
1985 callout_address = NULL;
1986 submission_name = NULL; /* Can be set by ACL */
1987 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1988 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1989 sender_verified_list = NULL; /* No senders verified */
1990 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1991 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1992
1993 authenticated_sender = NULL;
1994 #ifdef EXPERIMENTAL_BRIGHTMAIL
1995 bmi_run = 0;
1996 bmi_verdicts = NULL;
1997 #endif
1998 dnslist_domain = dnslist_matched = NULL;
1999 #ifndef DISABLE_DKIM
2000 dkim_signers = NULL;
2001 dkim_disable_verify = FALSE;
2002 dkim_collect_input = FALSE;
2003 #endif
2004 dsn_ret = 0;
2005 dsn_envid = NULL;
2006 deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
2007 #ifndef DISABLE_PRDR
2008 prdr_requested = FALSE;
2009 #endif
2010 #ifdef EXPERIMENTAL_SPF
2011 spf_header_comment = NULL;
2012 spf_received = NULL;
2013 spf_result = NULL;
2014 spf_smtp_comment = NULL;
2015 #endif
2016 #ifdef SUPPORT_I18N
2017 message_smtputf8 = FALSE;
2018 #endif
2019 body_linecount = body_zerocount = 0;
2020
2021 sender_rate = sender_rate_limit = sender_rate_period = NULL;
2022 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2023 /* Note that ratelimiters_conn persists across resets. */
2024
2025 /* Reset message ACL variables */
2026
2027 acl_var_m = NULL;
2028
2029 /* The message body variables use malloc store. They may be set if this is
2030 not the first message in an SMTP session and the previous message caused them
2031 to be referenced in an ACL. */
2032
2033 if (message_body)
2034 {
2035 store_free(message_body);
2036 message_body = NULL;
2037 }
2038
2039 if (message_body_end)
2040 {
2041 store_free(message_body_end);
2042 message_body_end = NULL;
2043 }
2044
2045 /* Warning log messages are also saved in malloc store. They are saved to avoid
2046 repetition in the same message, but it seems right to repeat them for different
2047 messages. */
2048
2049 while (acl_warn_logged)
2050 {
2051 string_item *this = acl_warn_logged;
2052 acl_warn_logged = acl_warn_logged->next;
2053 store_free(this);
2054 }
2055 store_reset(reset_point);
2056 }
2057
2058
2059
2060
2061
2062 /*************************************************
2063 * Initialize for incoming batched SMTP message *
2064 *************************************************/
2065
2066 /* This function is called from smtp_setup_msg() in the case when
2067 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2068 of messages in one file with SMTP commands between them. All errors must be
2069 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2070 relevant. After an error on a sender, or an invalid recipient, the remainder
2071 of the message is skipped. The value of received_protocol is already set.
2072
2073 Argument: none
2074 Returns: > 0 message successfully started (reached DATA)
2075 = 0 QUIT read or end of file reached
2076 < 0 should not occur
2077 */
2078
2079 static int
2080 smtp_setup_batch_msg(void)
2081 {
2082 int done = 0;
2083 void *reset_point = store_get(0);
2084
2085 /* Save the line count at the start of each transaction - single commands
2086 like HELO and RSET count as whole transactions. */
2087
2088 bsmtp_transaction_linecount = receive_linecount;
2089
2090 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2091
2092 cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
2093 smtp_reset(reset_point); /* Reset for start of message */
2094
2095 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2096 value. The values are 2 larger than the required yield of the function. */
2097
2098 while (done <= 0)
2099 {
2100 uschar *errmess;
2101 uschar *recipient = NULL;
2102 int start, end, sender_domain, recipient_domain;
2103
2104 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
2105 {
2106 /* The HELO/EHLO commands set sender_address_helo if they have
2107 valid data; otherwise they are ignored, except that they do
2108 a reset of the state. */
2109
2110 case HELO_CMD:
2111 case EHLO_CMD:
2112
2113 check_helo(smtp_cmd_data);
2114 /* Fall through */
2115
2116 case RSET_CMD:
2117 cancel_cutthrough_connection(TRUE, US"RSET received");
2118 smtp_reset(reset_point);
2119 bsmtp_transaction_linecount = receive_linecount;
2120 break;
2121
2122
2123 /* The MAIL FROM command requires an address as an operand. All we
2124 do here is to parse it for syntactic correctness. The form "<>" is
2125 a special case which converts into an empty string. The start/end
2126 pointers in the original are not used further for this address, as
2127 it is the canonical extracted address which is all that is kept. */
2128
2129 case MAIL_CMD:
2130 smtp_mailcmd_count++; /* Count for no-mail log */
2131 if (sender_address != NULL)
2132 /* The function moan_smtp_batch() does not return. */
2133 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
2134
2135 if (smtp_cmd_data[0] == 0)
2136 /* The function moan_smtp_batch() does not return. */
2137 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
2138
2139 /* Reset to start of message */
2140
2141 cancel_cutthrough_connection(TRUE, US"MAIL received");
2142 smtp_reset(reset_point);
2143
2144 /* Apply SMTP rewrite */
2145
2146 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2147 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2148 US"", global_rewrite_rules) : smtp_cmd_data;
2149
2150 /* Extract the address; the TRUE flag allows <> as valid */
2151
2152 raw_sender =
2153 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2154 TRUE);
2155
2156 if (raw_sender == NULL)
2157 /* The function moan_smtp_batch() does not return. */
2158 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2159
2160 sender_address = string_copy(raw_sender);
2161
2162 /* Qualify unqualified sender addresses if permitted to do so. */
2163
2164 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
2165 {
2166 if (allow_unqualified_sender)
2167 {
2168 sender_address = rewrite_address_qualify(sender_address, FALSE);
2169 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2170 "and rewritten\n", raw_sender);
2171 }
2172 /* The function moan_smtp_batch() does not return. */
2173 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2174 "a domain");
2175 }
2176 break;
2177
2178
2179 /* The RCPT TO command requires an address as an operand. All we do
2180 here is to parse it for syntactic correctness. There may be any number
2181 of RCPT TO commands, specifying multiple senders. We build them all into
2182 a data structure that is in argc/argv format. The start/end values
2183 given by parse_extract_address are not used, as we keep only the
2184 extracted address. */
2185
2186 case RCPT_CMD:
2187 if (sender_address == NULL)
2188 /* The function moan_smtp_batch() does not return. */
2189 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
2190
2191 if (smtp_cmd_data[0] == 0)
2192 /* The function moan_smtp_batch() does not return. */
2193 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
2194
2195 /* Check maximum number allowed */
2196
2197 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2198 /* The function moan_smtp_batch() does not return. */
2199 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2200 recipients_max_reject? "552": "452");
2201
2202 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2203 recipient address */
2204
2205 recipient = rewrite_existflags & rewrite_smtp
2206 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2207 global_rewrite_rules)
2208 : smtp_cmd_data;
2209
2210 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2211 &recipient_domain, FALSE);
2212
2213 if (!recipient)
2214 /* The function moan_smtp_batch() does not return. */
2215 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
2216
2217 /* If the recipient address is unqualified, qualify it if permitted. Then
2218 add it to the list of recipients. */
2219
2220 if (recipient_domain == 0)
2221 {
2222 if (allow_unqualified_recipient)
2223 {
2224 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2225 recipient);
2226 recipient = rewrite_address_qualify(recipient, TRUE);
2227 }
2228 /* The function moan_smtp_batch() does not return. */
2229 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
2230 "a domain");
2231 }
2232 receive_add_recipient(recipient, -1);
2233 break;
2234
2235
2236 /* The DATA command is legal only if it follows successful MAIL FROM
2237 and RCPT TO commands. This function is complete when a valid DATA
2238 command is encountered. */
2239
2240 case DATA_CMD:
2241 if (sender_address == NULL || recipients_count <= 0)
2242 {
2243 /* The function moan_smtp_batch() does not return. */
2244 if (sender_address == NULL)
2245 moan_smtp_batch(smtp_cmd_buffer,
2246 "503 MAIL FROM:<sender> command must precede DATA");
2247 else
2248 moan_smtp_batch(smtp_cmd_buffer,
2249 "503 RCPT TO:<recipient> must precede DATA");
2250 }
2251 else
2252 {
2253 done = 3; /* DATA successfully achieved */
2254 message_ended = END_NOTENDED; /* Indicate in middle of message */
2255 }
2256 break;
2257
2258
2259 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2260
2261 case VRFY_CMD:
2262 case EXPN_CMD:
2263 case HELP_CMD:
2264 case NOOP_CMD:
2265 case ETRN_CMD:
2266 bsmtp_transaction_linecount = receive_linecount;
2267 break;
2268
2269
2270 case EOF_CMD:
2271 case QUIT_CMD:
2272 done = 2;
2273 break;
2274
2275
2276 case BADARG_CMD:
2277 /* The function moan_smtp_batch() does not return. */
2278 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2279 break;
2280
2281
2282 case BADCHAR_CMD:
2283 /* The function moan_smtp_batch() does not return. */
2284 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2285 break;
2286
2287
2288 default:
2289 /* The function moan_smtp_batch() does not return. */
2290 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2291 break;
2292 }
2293 }
2294
2295 return done - 2; /* Convert yield values */
2296 }
2297
2298
2299
2300
2301 static BOOL
2302 smtp_log_tls_fail(uschar * errstr)
2303 {
2304 uschar * conn_info = smtp_get_connection_info();
2305
2306 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2307 /* I'd like to get separated H= here, but too hard for now */
2308
2309 log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2310 return FALSE;
2311 }
2312
2313
2314 /*************************************************
2315 * Start an SMTP session *
2316 *************************************************/
2317
2318 /* This function is called at the start of an SMTP session. Thereafter,
2319 smtp_setup_msg() is called to initiate each separate message. This
2320 function does host-specific testing, and outputs the banner line.
2321
2322 Arguments: none
2323 Returns: FALSE if the session can not continue; something has
2324 gone wrong, or the connection to the host is blocked
2325 */
2326
2327 BOOL
2328 smtp_start_session(void)
2329 {
2330 int size = 256;
2331 int ptr, esclen;
2332 uschar *user_msg, *log_msg;
2333 uschar *code, *esc;
2334 uschar *p, *s, *ss;
2335
2336 smtp_connection_start = time(NULL);
2337 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2338 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2339 smtp_ch_index = 0;
2340
2341 /* Default values for certain variables */
2342
2343 helo_seen = esmtp = helo_accept_junk = FALSE;
2344 smtp_mailcmd_count = 0;
2345 count_nonmail = TRUE_UNSET;
2346 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2347 smtp_delay_mail = smtp_rlm_base;
2348 auth_advertised = FALSE;
2349 pipelining_advertised = FALSE;
2350 pipelining_enable = TRUE;
2351 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2352 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2353
2354 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2355 authentication settings from -oMaa to remain in force. */
2356
2357 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
2358 authenticated_by = NULL;
2359
2360 #ifdef SUPPORT_TLS
2361 tls_in.cipher = tls_in.peerdn = NULL;
2362 tls_in.ourcert = tls_in.peercert = NULL;
2363 tls_in.sni = NULL;
2364 tls_in.ocsp = OCSP_NOT_REQ;
2365 tls_advertised = FALSE;
2366 #endif
2367 dsn_advertised = FALSE;
2368 #ifdef SUPPORT_I18N
2369 smtputf8_advertised = FALSE;
2370 #endif
2371
2372 /* Reset ACL connection variables */
2373
2374 acl_var_c = NULL;
2375
2376 /* Allow for trailing 0 in the command and data buffers. */
2377
2378 if (!(smtp_cmd_buffer = US malloc(2*SMTP_CMD_BUFFER_SIZE + 2)))
2379 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2380 "malloc() failed for SMTP command buffer");
2381
2382 smtp_cmd_buffer[0] = 0;
2383 smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
2384
2385 /* For batched input, the protocol setting can be overridden from the
2386 command line by a trusted caller. */
2387
2388 if (smtp_batched_input)
2389 {
2390 if (!received_protocol) received_protocol = US"local-bsmtp";
2391 }
2392
2393 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2394 reset later if any of EHLO/AUTH/STARTTLS are received. */
2395
2396 else
2397 received_protocol =
2398 (sender_host_address ? protocols : protocols_local) [pnormal];
2399
2400 /* Set up the buffer for inputting using direct read() calls, and arrange to
2401 call the local functions instead of the standard C ones. */
2402
2403 if (!(smtp_inbuffer = (uschar *)malloc(IN_BUFFER_SIZE)))
2404 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2405
2406 receive_getc = smtp_getc;
2407 receive_getbuf = smtp_getbuf;
2408 receive_get_cache = smtp_get_cache;
2409 receive_ungetc = smtp_ungetc;
2410 receive_feof = smtp_feof;
2411 receive_ferror = smtp_ferror;
2412 receive_smtp_buffered = smtp_buffered;
2413 smtp_inptr = smtp_inend = smtp_inbuffer;
2414 smtp_had_eof = smtp_had_error = 0;
2415
2416 /* Set up the message size limit; this may be host-specific */
2417
2418 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2419 if (expand_string_message != NULL)
2420 {
2421 if (thismessage_size_limit == -1)
2422 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2423 "%s", expand_string_message);
2424 else
2425 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2426 "%s", expand_string_message);
2427 smtp_closedown(US"Temporary local problem - please try later");
2428 return FALSE;
2429 }
2430
2431 /* When a message is input locally via the -bs or -bS options, sender_host_
2432 unknown is set unless -oMa was used to force an IP address, in which case it
2433 is checked like a real remote connection. When -bs is used from inetd, this
2434 flag is not set, causing the sending host to be checked. The code that deals
2435 with IP source routing (if configured) is never required for -bs or -bS and
2436 the flag sender_host_notsocket is used to suppress it.
2437
2438 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2439 reserve for certain hosts and/or networks. */
2440
2441 if (!sender_host_unknown)
2442 {
2443 int rc;
2444 BOOL reserved_host = FALSE;
2445
2446 /* Look up IP options (source routing info) on the socket if this is not an
2447 -oMa "host", and if any are found, log them and drop the connection.
2448
2449 Linux (and others now, see below) is different to everyone else, so there
2450 has to be some conditional compilation here. Versions of Linux before 2.1.15
2451 used a structure whose name was "options". Somebody finally realized that
2452 this name was silly, and it got changed to "ip_options". I use the
2453 newer name here, but there is a fudge in the script that sets up os.h
2454 to define a macro in older Linux systems.
2455
2456 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2457 glibc 2, which has chosen ip_opts for the structure name. This is now
2458 really a glibc thing rather than a Linux thing, so the condition name
2459 has been changed to reflect this. It is relevant also to GNU/Hurd.
2460
2461 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2462 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2463 a special macro defined in the os.h file.
2464
2465 Some DGUX versions on older hardware appear not to support IP options at
2466 all, so there is now a general macro which can be set to cut out this
2467 support altogether.
2468
2469 How to do this properly in IPv6 is not yet known. */
2470
2471 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2472
2473 #ifdef GLIBC_IP_OPTIONS
2474 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2475 #define OPTSTYLE 1
2476 #else
2477 #define OPTSTYLE 2
2478 #endif
2479 #elif defined DARWIN_IP_OPTIONS
2480 #define OPTSTYLE 2
2481 #else
2482 #define OPTSTYLE 3
2483 #endif
2484
2485 if (!host_checking && !sender_host_notsocket)
2486 {
2487 #if OPTSTYLE == 1
2488 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2489 struct ip_options *ipopt = store_get(optlen);
2490 #elif OPTSTYLE == 2
2491 struct ip_opts ipoptblock;
2492 struct ip_opts *ipopt = &ipoptblock;
2493 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2494 #else
2495 struct ipoption ipoptblock;
2496 struct ipoption *ipopt = &ipoptblock;
2497 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2498 #endif
2499
2500 /* Occasional genuine failures of getsockopt() have been seen - for
2501 example, "reset by peer". Therefore, just log and give up on this
2502 call, unless the error is ENOPROTOOPT. This error is given by systems
2503 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2504 of writing. So for that error, carry on - we just can't do an IP options
2505 check. */
2506
2507 DEBUG(D_receive) debug_printf("checking for IP options\n");
2508
2509 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
2510 &optlen) < 0)
2511 {
2512 if (errno != ENOPROTOOPT)
2513 {
2514 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2515 host_and_ident(FALSE), strerror(errno));
2516 smtp_printf("451 SMTP service not available\r\n", FALSE);
2517 return FALSE;
2518 }
2519 }
2520
2521 /* Deal with any IP options that are set. On the systems I have looked at,
2522 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2523 more logging data than will fit in big_buffer. Nevertheless, after somebody
2524 questioned this code, I've added in some paranoid checking. */
2525
2526 else if (optlen > 0)
2527 {
2528 uschar *p = big_buffer;
2529 uschar *pend = big_buffer + big_buffer_size;
2530 uschar *opt, *adptr;
2531 int optcount;
2532 struct in_addr addr;
2533
2534 #if OPTSTYLE == 1
2535 uschar *optstart = (uschar *)(ipopt->__data);
2536 #elif OPTSTYLE == 2
2537 uschar *optstart = (uschar *)(ipopt->ip_opts);
2538 #else
2539 uschar *optstart = (uschar *)(ipopt->ipopt_list);
2540 #endif
2541
2542 DEBUG(D_receive) debug_printf("IP options exist\n");
2543
2544 Ustrcpy(p, "IP options on incoming call:");
2545 p += Ustrlen(p);
2546
2547 for (opt = optstart; opt != NULL &&
2548 opt < (uschar *)(ipopt) + optlen;)
2549 {
2550 switch (*opt)
2551 {
2552 case IPOPT_EOL:
2553 opt = NULL;
2554 break;
2555
2556 case IPOPT_NOP:
2557 opt++;
2558 break;
2559
2560 case IPOPT_SSRR:
2561 case IPOPT_LSRR:
2562 if (!string_format(p, pend-p, " %s [@%s",
2563 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2564 #if OPTSTYLE == 1
2565 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2566 #elif OPTSTYLE == 2
2567 inet_ntoa(ipopt->ip_dst)))
2568 #else
2569 inet_ntoa(ipopt->ipopt_dst)))
2570 #endif
2571 {
2572 opt = NULL;
2573 break;
2574 }
2575
2576 p += Ustrlen(p);
2577 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2578 adptr = opt + 3;
2579 while (optcount-- > 0)
2580 {
2581 memcpy(&addr, adptr, sizeof(addr));
2582 if (!string_format(p, pend - p - 1, "%s%s",
2583 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2584 {
2585 opt = NULL;
2586 break;
2587 }
2588 p += Ustrlen(p);
2589 adptr += sizeof(struct in_addr);
2590 }
2591 *p++ = ']';
2592 opt += opt[1];
2593 break;
2594
2595 default:
2596 {
2597 int i;
2598 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2599 Ustrcat(p, "[ ");
2600 p += 2;
2601 for (i = 0; i < opt[1]; i++)
2602 {
2603 sprintf(CS p, "%2.2x ", opt[i]);
2604 p += 3;
2605 }
2606 *p++ = ']';
2607 }
2608 opt += opt[1];
2609 break;
2610 }
2611 }
2612
2613 *p = 0;
2614 log_write(0, LOG_MAIN, "%s", big_buffer);
2615
2616 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2617
2618 log_write(0, LOG_MAIN|LOG_REJECT,
2619 "connection from %s refused (IP options)", host_and_ident(FALSE));
2620
2621 smtp_printf("554 SMTP service not available\r\n", FALSE);
2622 return FALSE;
2623 }
2624
2625 /* Length of options = 0 => there are no options */
2626
2627 else DEBUG(D_receive) debug_printf("no IP options found\n");
2628 }
2629 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2630
2631 /* Set keep-alive in socket options. The option is on by default. This
2632 setting is an attempt to get rid of some hanging connections that stick in
2633 read() when the remote end (usually a dialup) goes away. */
2634
2635 if (smtp_accept_keepalive && !sender_host_notsocket)
2636 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2637
2638 /* If the current host matches host_lookup, set the name by doing a
2639 reverse lookup. On failure, sender_host_name will be NULL and
2640 host_lookup_failed will be TRUE. This may or may not be serious - optional
2641 checks later. */
2642
2643 if (verify_check_host(&host_lookup) == OK)
2644 {
2645 (void)host_name_lookup();
2646 host_build_sender_fullhost();
2647 }
2648
2649 /* Delay this until we have the full name, if it is looked up. */
2650
2651 set_process_info("handling incoming connection from %s",
2652 host_and_ident(FALSE));
2653
2654 /* Expand smtp_receive_timeout, if needed */
2655
2656 if (smtp_receive_timeout_s)
2657 {
2658 uschar * exp;
2659 if ( !(exp = expand_string(smtp_receive_timeout_s))
2660 || !(*exp)
2661 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2662 )
2663 log_write(0, LOG_MAIN|LOG_PANIC,
2664 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2665 }
2666
2667 /* Test for explicit connection rejection */
2668
2669 if (verify_check_host(&host_reject_connection) == OK)
2670 {
2671 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2672 "from %s (host_reject_connection)", host_and_ident(FALSE));
2673 smtp_printf("554 SMTP service not available\r\n", FALSE);
2674 return FALSE;
2675 }
2676
2677 /* Test with TCP Wrappers if so configured. There is a problem in that
2678 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2679 such as disks dying. In these cases, it is desirable to reject with a 4xx
2680 error instead of a 5xx error. There isn't a "right" way to detect such
2681 problems. The following kludge is used: errno is zeroed before calling
2682 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2683 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2684 not exist). */
2685
2686 #ifdef USE_TCP_WRAPPERS
2687 errno = 0;
2688 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
2689 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2690 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2691 expand_string_message);
2692
2693 if (!hosts_ctl(tcp_wrappers_name,
2694 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2695 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2696 sender_ident ? CS sender_ident : STRING_UNKNOWN))
2697 {
2698 if (errno == 0 || errno == ENOENT)
2699 {
2700 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2701 log_write(L_connection_reject,
2702 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2703 "(tcp wrappers)", host_and_ident(FALSE));
2704 smtp_printf("554 SMTP service not available\r\n", FALSE);
2705 }
2706 else
2707 {
2708 int save_errno = errno;
2709 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2710 "errno value %d\n", save_errno);
2711 log_write(L_connection_reject,
2712 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2713 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2714 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
2715 }
2716 return FALSE;
2717 }
2718 #endif
2719
2720 /* Check for reserved slots. The value of smtp_accept_count has already been
2721 incremented to include this process. */
2722
2723 if (smtp_accept_max > 0 &&
2724 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2725 {
2726 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2727 {
2728 log_write(L_connection_reject,
2729 LOG_MAIN, "temporarily refused connection from %s: not in "
2730 "reserve list: connected=%d max=%d reserve=%d%s",
2731 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2732 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2733 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2734 "please try again later\r\n", FALSE, smtp_active_hostname);
2735 return FALSE;
2736 }
2737 reserved_host = TRUE;
2738 }
2739
2740 /* If a load level above which only messages from reserved hosts are
2741 accepted is set, check the load. For incoming calls via the daemon, the
2742 check is done in the superior process if there are no reserved hosts, to
2743 save a fork. In all cases, the load average will already be available
2744 in a global variable at this point. */
2745
2746 if (smtp_load_reserve >= 0 &&
2747 load_average > smtp_load_reserve &&
2748 !reserved_host &&
2749 verify_check_host(&smtp_reserve_hosts) != OK)
2750 {
2751 log_write(L_connection_reject,
2752 LOG_MAIN, "temporarily refused connection from %s: not in "
2753 "reserve list and load average = %.2f", host_and_ident(FALSE),
2754 (double)load_average/1000.0);
2755 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
2756 smtp_active_hostname);
2757 return FALSE;
2758 }
2759
2760 /* Determine whether unqualified senders or recipients are permitted
2761 for this host. Unfortunately, we have to do this every time, in order to
2762 set the flags so that they can be inspected when considering qualifying
2763 addresses in the headers. For a site that permits no qualification, this
2764 won't take long, however. */
2765
2766 allow_unqualified_sender =
2767 verify_check_host(&sender_unqualified_hosts) == OK;
2768
2769 allow_unqualified_recipient =
2770 verify_check_host(&recipient_unqualified_hosts) == OK;
2771
2772 /* Determine whether HELO/EHLO is required for this host. The requirement
2773 can be hard or soft. */
2774
2775 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2776 if (!helo_required)
2777 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2778
2779 /* Determine whether this hosts is permitted to send syntactic junk
2780 after a HELO or EHLO command. */
2781
2782 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2783 }
2784
2785 /* For batch SMTP input we are now done. */
2786
2787 if (smtp_batched_input) return TRUE;
2788
2789 /* If valid Proxy Protocol source is connecting, set up session.
2790 * Failure will not allow any SMTP function other than QUIT. */
2791
2792 #ifdef SUPPORT_PROXY
2793 proxy_session = FALSE;
2794 proxy_session_failed = FALSE;
2795 if (check_proxy_protocol_host())
2796 setup_proxy_protocol_host();
2797 #endif
2798
2799 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2800 smtps port for use with older style SSL MTAs. */
2801
2802 #ifdef SUPPORT_TLS
2803 if (tls_in.on_connect && tls_server_start(tls_require_ciphers, &user_msg) != OK)
2804 return smtp_log_tls_fail(user_msg);
2805 #endif
2806
2807 /* Run the connect ACL if it exists */
2808
2809 user_msg = NULL;
2810 if (acl_smtp_connect)
2811 {
2812 int rc;
2813 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2814 &log_msg)) != OK)
2815 {
2816 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2817 return FALSE;
2818 }
2819 }
2820
2821 /* Output the initial message for a two-way SMTP connection. It may contain
2822 newlines, which then cause a multi-line response to be given. */
2823
2824 code = US"220"; /* Default status code */
2825 esc = US""; /* Default extended status code */
2826 esclen = 0; /* Length of esc */
2827
2828 if (!user_msg)
2829 {
2830 if (!(s = expand_string(smtp_banner)))
2831 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2832 "failed: %s", smtp_banner, expand_string_message);
2833 }
2834 else
2835 {
2836 int codelen = 3;
2837 s = user_msg;
2838 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2839 if (codelen > 4)
2840 {
2841 esc = code + 4;
2842 esclen = codelen - 4;
2843 }
2844 }
2845
2846 /* Remove any terminating newlines; might as well remove trailing space too */
2847
2848 p = s + Ustrlen(s);
2849 while (p > s && isspace(p[-1])) p--;
2850 *p = 0;
2851
2852 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2853 is all contained in a single IP packet. The original code wrote out the
2854 greeting using several calls to fprint/fputc, and on busy servers this could
2855 cause it to be split over more than one packet - which caused CC:Mail to fall
2856 over when it got the second part of the greeting after sending its first
2857 command. Sigh. To try to avoid this, build the complete greeting message
2858 first, and output it in one fell swoop. This gives a better chance of it
2859 ending up as a single packet. */
2860
2861 ss = store_get(size);
2862 ptr = 0;
2863
2864 p = s;
2865 do /* At least once, in case we have an empty string */
2866 {
2867 int len;
2868 uschar *linebreak = Ustrchr(p, '\n');
2869 ss = string_catn(ss, &size, &ptr, code, 3);
2870 if (linebreak == NULL)
2871 {
2872 len = Ustrlen(p);
2873 ss = string_catn(ss, &size, &ptr, US" ", 1);
2874 }
2875 else
2876 {
2877 len = linebreak - p;
2878 ss = string_catn(ss, &size, &ptr, US"-", 1);
2879 }
2880 ss = string_catn(ss, &size, &ptr, esc, esclen);
2881 ss = string_catn(ss, &size, &ptr, p, len);
2882 ss = string_catn(ss, &size, &ptr, US"\r\n", 2);
2883 p += len;
2884 if (linebreak != NULL) p++;
2885 }
2886 while (*p != 0);
2887
2888 ss[ptr] = 0; /* string_cat leaves room for this */
2889
2890 /* Before we write the banner, check that there is no input pending, unless
2891 this synchronisation check is disabled. */
2892
2893 if (!check_sync())
2894 {
2895 unsigned n = smtp_inend - smtp_inptr;
2896 if (n > 32) n = 32;
2897
2898 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2899 "synchronization error (input sent without waiting for greeting): "
2900 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2901 string_printing(string_copyn(smtp_inptr, n)));
2902 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
2903 return FALSE;
2904 }
2905
2906 /* Now output the banner */
2907
2908 smtp_printf("%s", FALSE, ss);
2909 return TRUE;
2910 }
2911
2912
2913
2914
2915
2916 /*************************************************
2917 * Handle SMTP syntax and protocol errors *
2918 *************************************************/
2919
2920 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2921 to do so. Then transmit the error response. The return value depends on the
2922 number of syntax and protocol errors in this SMTP session.
2923
2924 Arguments:
2925 type error type, given as a log flag bit
2926 code response code; <= 0 means don't send a response
2927 data data to reflect in the response (can be NULL)
2928 errmess the error message
2929
2930 Returns: -1 limit of syntax/protocol errors NOT exceeded
2931 +1 limit of syntax/protocol errors IS exceeded
2932
2933 These values fit in with the values of the "done" variable in the main
2934 processing loop in smtp_setup_msg(). */
2935
2936 static int
2937 synprot_error(int type, int code, uschar *data, uschar *errmess)
2938 {
2939 int yield = -1;
2940
2941 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2942 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2943 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2944
2945 if (++synprot_error_count > smtp_max_synprot_errors)
2946 {
2947 yield = 1;
2948 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2949 "syntax or protocol errors (last command was \"%s\")",
2950 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
2951 }
2952
2953 if (code > 0)
2954 {
2955 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
2956 data ? data : US"", data ? US": " : US"", errmess);
2957 if (yield == 1)
2958 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
2959 }
2960
2961 return yield;
2962 }
2963
2964
2965
2966
2967 /*************************************************
2968 * Send SMTP response, possibly multiline *
2969 *************************************************/
2970
2971 /* There are, it seems, broken clients out there that cannot handle multiline
2972 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2973 output nothing for non-final calls, and only the first line for anything else.
2974
2975 Arguments:
2976 code SMTP code, may involve extended status codes
2977 codelen length of smtp code; if > 4 there's an ESC
2978 final FALSE if the last line isn't the final line
2979 msg message text, possibly containing newlines
2980
2981 Returns: nothing
2982 */
2983
2984 void
2985 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2986 {
2987 int esclen = 0;
2988 uschar *esc = US"";
2989
2990 if (!final && no_multiline_responses) return;
2991
2992 if (codelen > 4)
2993 {
2994 esc = code + 4;
2995 esclen = codelen - 4;
2996 }
2997
2998 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2999 have had the same. Note: this code is also present in smtp_printf(). It would
3000 be tidier to have it only in one place, but when it was added, it was easier to
3001 do it that way, so as not to have to mess with the code for the RCPT command,
3002 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3003
3004 if (rcpt_in_progress)
3005 {
3006 if (rcpt_smtp_response == NULL)
3007 rcpt_smtp_response = string_copy(msg);
3008 else if (rcpt_smtp_response_same &&
3009 Ustrcmp(rcpt_smtp_response, msg) != 0)
3010 rcpt_smtp_response_same = FALSE;
3011 rcpt_in_progress = FALSE;
3012 }
3013
3014 /* Now output the message, splitting it up into multiple lines if necessary.
3015 We only handle pipelining these responses as far as nonfinal/final groups,
3016 not the whole MAIL/RCPT/DATA response set. */
3017
3018 for (;;)
3019 {
3020 uschar *nl = Ustrchr(msg, '\n');
3021 if (nl == NULL)
3022 {
3023 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
3024 return;
3025 }
3026 else if (nl[1] == 0 || no_multiline_responses)
3027 {
3028 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
3029 (int)(nl - msg), msg);
3030 return;
3031 }
3032 else
3033 {
3034 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
3035 msg = nl + 1;
3036 while (isspace(*msg)) msg++;
3037 }
3038 }
3039 }
3040
3041
3042
3043
3044 /*************************************************
3045 * Parse user SMTP message *
3046 *************************************************/
3047
3048 /* This function allows for user messages overriding the response code details
3049 by providing a suitable response code string at the start of the message
3050 user_msg. Check the message for starting with a response code and optionally an
3051 extended status code. If found, check that the first digit is valid, and if so,
3052 change the code pointer and length to use the replacement. An invalid code
3053 causes a panic log; in this case, if the log messages is the same as the user
3054 message, we must also adjust the value of the log message to show the code that
3055 is actually going to be used (the original one).
3056
3057 This function is global because it is called from receive.c as well as within
3058 this module.
3059
3060 Note that the code length returned includes the terminating whitespace
3061 character, which is always included in the regex match.
3062
3063 Arguments:
3064 code SMTP code, may involve extended status codes
3065 codelen length of smtp code; if > 4 there's an ESC
3066 msg message text
3067 log_msg optional log message, to be adjusted with the new SMTP code
3068 check_valid if true, verify the response code
3069
3070 Returns: nothing
3071 */
3072
3073 void
3074 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3075 BOOL check_valid)
3076 {
3077 int n;
3078 int ovector[3];
3079
3080 if (!msg || !*msg) return;
3081
3082 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3083 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
3084
3085 if (check_valid && (*msg)[0] != (*code)[0])
3086 {
3087 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3088 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3089 if (log_msg != NULL && *log_msg == *msg)
3090 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3091 }
3092 else
3093 {
3094 *code = *msg;
3095 *codelen = ovector[1]; /* Includes final space */
3096 }
3097 *msg += ovector[1]; /* Chop the code off the message */
3098 return;
3099 }
3100
3101
3102
3103
3104 /*************************************************
3105 * Handle an ACL failure *
3106 *************************************************/
3107
3108 /* This function is called when acl_check() fails. As well as calls from within
3109 this module, it is called from receive.c for an ACL after DATA. It sorts out
3110 logging the incident, and sets up the error response. A message containing
3111 newlines is turned into a multiline SMTP response, but for logging, only the
3112 first line is used.
3113
3114 There's a table of default permanent failure response codes to use in
3115 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3116 defaults disabled in Exim. However, discussion in connection with RFC 821bis
3117 (aka RFC 2821) has concluded that the response should be 252 in the disabled
3118 state, because there are broken clients that try VRFY before RCPT. A 5xx
3119 response should be given only when the address is positively known to be
3120 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3121 no explicit code, but if there is one we let it know best.
3122 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
3123
3124 From Exim 4.63, it is possible to override the response code details by
3125 providing a suitable response code string at the start of the message provided
3126 in user_msg. The code's first digit is checked for validity.
3127
3128 Arguments:
3129 where where the ACL was called from
3130 rc the failure code
3131 user_msg a message that can be included in an SMTP response
3132 log_msg a message for logging
3133
3134 Returns: 0 in most cases
3135 2 if the failure code was FAIL_DROP, in which case the
3136 SMTP connection should be dropped (this value fits with the
3137 "done" variable in smtp_setup_msg() below)
3138 */
3139
3140 int
3141 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3142 {
3143 BOOL drop = rc == FAIL_DROP;
3144 int codelen = 3;
3145 uschar *smtp_code;
3146 uschar *lognl;
3147 uschar *sender_info = US"";
3148 uschar *what =
3149 #ifdef WITH_CONTENT_SCAN
3150 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
3151 #endif
3152 where == ACL_WHERE_PREDATA ? US"DATA" :
3153 where == ACL_WHERE_DATA ? US"after DATA" :
3154 #ifndef DISABLE_PRDR
3155 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
3156 #endif
3157 smtp_cmd_data ?
3158 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3159 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
3160
3161 if (drop) rc = FAIL;
3162
3163 /* Set the default SMTP code, and allow a user message to change it. */
3164
3165 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3166 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3167 where != ACL_WHERE_VRFY);
3168
3169 /* We used to have sender_address here; however, there was a bug that was not
3170 updating sender_address after a rewrite during a verify. When this bug was
3171 fixed, sender_address at this point became the rewritten address. I'm not sure
3172 this is what should be logged, so I've changed to logging the unrewritten
3173 address to retain backward compatibility. */
3174
3175 #ifndef WITH_CONTENT_SCAN
3176 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
3177 #else
3178 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3179 #endif
3180 {
3181 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3182 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3183 sender_host_authenticated ? US" A=" : US"",
3184 sender_host_authenticated ? sender_host_authenticated : US"",
3185 sender_host_authenticated && authenticated_id ? US":" : US"",
3186 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3187 );
3188 }
3189
3190 /* If there's been a sender verification failure with a specific message, and
3191 we have not sent a response about it yet, do so now, as a preliminary line for
3192 failures, but not defers. However, always log it for defer, and log it for fail
3193 unless the sender_verify_fail log selector has been turned off. */
3194
3195 if (sender_verified_failed &&
3196 !testflag(sender_verified_failed, af_sverify_told))
3197 {
3198 BOOL save_rcpt_in_progress = rcpt_in_progress;
3199 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3200
3201 setflag(sender_verified_failed, af_sverify_told);
3202
3203 if (rc != FAIL || LOGGING(sender_verify_fail))
3204 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3205 host_and_ident(TRUE),
3206 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3207 sender_verified_failed->address,
3208 (sender_verified_failed->message == NULL)? US"" :
3209 string_sprintf(": %s", sender_verified_failed->message));
3210
3211 if (rc == FAIL && sender_verified_failed->user_message)
3212 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
3213 testflag(sender_verified_failed, af_verify_pmfail)?
3214 "Postmaster verification failed while checking <%s>\n%s\n"
3215 "Several RFCs state that you are required to have a postmaster\n"
3216 "mailbox for each mail domain. This host does not accept mail\n"
3217 "from domains whose servers reject the postmaster address."
3218 :
3219 testflag(sender_verified_failed, af_verify_nsfail)?
3220 "Callback setup failed while verifying <%s>\n%s\n"
3221 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3222 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3223 "RFC requirements, and stops you from receiving standard bounce\n"
3224 "messages. This host does not accept mail from domains whose servers\n"
3225 "refuse bounces."
3226 :
3227 "Verification failed for <%s>\n%s",
3228 sender_verified_failed->address,
3229 sender_verified_failed->user_message));
3230
3231 rcpt_in_progress = save_rcpt_in_progress;
3232 }
3233
3234 /* Sort out text for logging */
3235
3236 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3237 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
3238
3239 /* Send permanent failure response to the command, but the code used isn't
3240 always a 5xx one - see comments at the start of this function. If the original
3241 rc was FAIL_DROP we drop the connection and yield 2. */
3242
3243 if (rc == FAIL)
3244 smtp_respond(smtp_code, codelen, TRUE,
3245 user_msg ? user_msg : US"Administrative prohibition");
3246
3247 /* Send temporary failure response to the command. Don't give any details,
3248 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3249 verb, and for a header verify when smtp_return_error_details is set.
3250
3251 This conditional logic is all somewhat of a mess because of the odd
3252 interactions between temp_details and return_error_details. One day it should
3253 be re-implemented in a tidier fashion. */
3254
3255 else
3256 if (acl_temp_details && user_msg)
3257 {
3258 if ( smtp_return_error_details
3259 && sender_verified_failed
3260 && sender_verified_failed->message
3261 )
3262 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
3263
3264 smtp_respond(smtp_code, codelen, TRUE, user_msg);
3265 }
3266 else
3267 smtp_respond(smtp_code, codelen, TRUE,
3268 US"Temporary local problem - please try later");
3269
3270 /* Log the incident to the logs that are specified by log_reject_target
3271 (default main, reject). This can be empty to suppress logging of rejections. If
3272 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3273 is closing if required and return 2. */
3274
3275 if (log_reject_target != 0)
3276 {
3277 #ifdef SUPPORT_TLS
3278 uschar * tls = s_tlslog(NULL, NULL, NULL);
3279 if (!tls) tls = US"";
3280 #else
3281 uschar * tls = US"";
3282 #endif
3283 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3284 log_reject_target, "%s%s%s %s%srejected %s%s",
3285 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3286 host_and_ident(TRUE),
3287 tls,
3288 sender_info,
3289 rc == FAIL ? US"" : US"temporarily ",
3290 what, log_msg);
3291 }
3292
3293 if (!drop) return 0;
3294
3295 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3296 smtp_get_connection_info());
3297
3298 /* Run the not-quit ACL, but without any custom messages. This should not be a
3299 problem, because we get here only if some other ACL has issued "drop", and
3300 in that case, *its* custom messages will have been used above. */
3301
3302 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3303 return 2;
3304 }
3305
3306
3307
3308
3309 /*************************************************
3310 * Handle SMTP exit when QUIT is not given *
3311 *************************************************/
3312
3313 /* This function provides a logging/statistics hook for when an SMTP connection
3314 is dropped on the floor or the other end goes away. It's a global function
3315 because it's called from receive.c as well as this module. As well as running
3316 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3317 response, either with a custom message from the ACL, or using a default. There
3318 is one case, however, when no message is output - after "drop". In that case,
3319 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3320 passed to this function.
3321
3322 In case things go wrong while processing this function, causing an error that
3323 may re-enter this function, there is a recursion check.
3324
3325 Arguments:
3326 reason What $smtp_notquit_reason will be set to in the ACL;
3327 if NULL, the ACL is not run
3328 code The error code to return as part of the response
3329 defaultrespond The default message if there's no user_msg
3330
3331 Returns: Nothing
3332 */
3333
3334 void
3335 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3336 {
3337 int rc;
3338 uschar *user_msg = NULL;
3339 uschar *log_msg = NULL;
3340
3341 /* Check for recursive acll */
3342
3343 if (smtp_exit_function_called)
3344 {
3345 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3346 reason);
3347 return;
3348 }
3349 smtp_exit_function_called = TRUE;
3350
3351 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3352
3353 if (acl_smtp_notquit && reason)
3354 {
3355 smtp_notquit_reason = reason;
3356 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3357 &log_msg)) == ERROR)
3358 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3359 log_msg);
3360 }
3361
3362 /* Write an SMTP response if we are expected to give one. As the default
3363 responses are all internal, they should always fit in the buffer, but code a
3364 warning, just in case. Note that string_vformat() still leaves a complete
3365 string, even if it is incomplete. */
3366
3367 if (code && defaultrespond)
3368 {
3369 if (user_msg)
3370 smtp_respond(code, 3, TRUE, user_msg);
3371 else
3372 {
3373 uschar buffer[128];
3374 va_list ap;
3375 va_start(ap, defaultrespond);
3376 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
3377 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
3378 smtp_printf("%s %s\r\n", FALSE, code, buffer);
3379 va_end(ap);
3380 }
3381 mac_smtp_fflush();
3382 }
3383 }
3384
3385
3386
3387
3388 /*************************************************
3389 * Verify HELO argument *
3390 *************************************************/
3391
3392 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3393 matched. It is also called from ACL processing if verify = helo is used and
3394 verification was not previously tried (i.e. helo_try_verify_hosts was not
3395 matched). The result of its processing is to set helo_verified and
3396 helo_verify_failed. These variables should both be FALSE for this function to
3397 be called.
3398
3399 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3400 for IPv6 ::ffff: literals.
3401
3402 Argument: none
3403 Returns: TRUE if testing was completed;
3404 FALSE on a temporary failure
3405 */
3406
3407 BOOL
3408 smtp_verify_helo(void)
3409 {
3410 BOOL yield = TRUE;
3411
3412 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3413 sender_helo_name);
3414
3415 if (sender_helo_name == NULL)
3416 {
3417 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3418 }
3419
3420 /* Deal with the case of -bs without an IP address */
3421
3422 else if (sender_host_address == NULL)
3423 {
3424 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3425 helo_verified = TRUE;
3426 }
3427
3428 /* Deal with the more common case when there is a sending IP address */
3429
3430 else if (sender_helo_name[0] == '[')
3431 {
3432 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3433 Ustrlen(sender_host_address)) == 0;
3434
3435 #if HAVE_IPV6
3436 if (!helo_verified)
3437 {
3438 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3439 helo_verified = Ustrncmp(sender_helo_name + 1,
3440 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3441 }
3442 #endif
3443
3444 HDEBUG(D_receive)
3445 { if (helo_verified) debug_printf("matched host address\n"); }
3446 }
3447
3448 /* Do a reverse lookup if one hasn't already given a positive or negative
3449 response. If that fails, or the name doesn't match, try checking with a forward
3450 lookup. */
3451
3452 else
3453 {
3454 if (sender_host_name == NULL && !host_lookup_failed)
3455 yield = host_name_lookup() != DEFER;
3456
3457 /* If a host name is known, check it and all its aliases. */
3458
3459 if (sender_host_name)
3460 if ((helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3461 {
3462 sender_helo_dnssec = sender_host_dnssec;
3463 HDEBUG(D_receive) debug_printf("matched host name\n");
3464 }
3465 else
3466 {
3467 uschar **aliases = sender_host_aliases;
3468 while (*aliases)
3469 if ((helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3470 {
3471 sender_helo_dnssec = sender_host_dnssec;
3472 break;
3473 }
3474
3475 HDEBUG(D_receive) if (helo_verified)
3476 debug_printf("matched alias %s\n", *(--aliases));
3477 }
3478
3479 /* Final attempt: try a forward lookup of the helo name */
3480
3481 if (!helo_verified)
3482 {
3483 int rc;
3484 host_item h;
3485 dnssec_domains d;
3486 host_item *hh;
3487
3488 h.name = sender_helo_name;
3489 h.address = NULL;
3490 h.mx = MX_NONE;
3491 h.next = NULL;
3492 d.request = US"*";
3493 d.require = US"";
3494
3495 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3496 sender_helo_name);
3497 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A,
3498 NULL, NULL, NULL, &d, NULL, NULL);
3499 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3500 for (hh = &h; hh; hh = hh->next)
3501 if (Ustrcmp(hh->address, sender_host_address) == 0)
3502 {
3503 helo_verified = TRUE;
3504 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3505 HDEBUG(D_receive)
3506 {
3507 debug_printf("IP address for %s matches calling address\n"
3508 "Forward DNS security status: %sverified\n",
3509 sender_helo_name, sender_helo_dnssec ? "" : "un");
3510 }
3511 break;
3512 }
3513 }
3514 }
3515
3516 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
3517 return yield;
3518 }
3519
3520
3521
3522
3523 /*************************************************
3524 * Send user response message *
3525 *************************************************/
3526
3527 /* This function is passed a default response code and a user message. It calls
3528 smtp_message_code() to check and possibly modify the response code, and then
3529 calls smtp_respond() to transmit the response. I put this into a function
3530 just to avoid a lot of repetition.
3531
3532 Arguments:
3533 code the response code
3534 user_msg the user message
3535
3536 Returns: nothing
3537 */
3538
3539 static void
3540 smtp_user_msg(uschar *code, uschar *user_msg)
3541 {
3542 int len = 3;
3543 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3544 smtp_respond(code, len, TRUE, user_msg);
3545 }
3546
3547
3548
3549 static int
3550 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3551 {
3552 const uschar *set_id = NULL;
3553 int rc, i;
3554
3555 /* Run the checking code, passing the remainder of the command line as
3556 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3557 it as the only set numerical variable. The authenticator may set $auth<n>
3558 and also set other numeric variables. The $auth<n> variables are preferred
3559 nowadays; the numerical variables remain for backwards compatibility.
3560
3561 Afterwards, have a go at expanding the set_id string, even if
3562 authentication failed - for bad passwords it can be useful to log the
3563 userid. On success, require set_id to expand and exist, and put it in
3564 authenticated_id. Save this in permanent store, as the working store gets
3565 reset at HELO, RSET, etc. */
3566
3567 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3568 expand_nmax = 0;
3569 expand_nlength[0] = 0; /* $0 contains nothing */
3570
3571 rc = (au->info->servercode)(au, smtp_cmd_data);
3572 if (au->set_id) set_id = expand_string(au->set_id);
3573 expand_nmax = -1; /* Reset numeric variables */
3574 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3575
3576 /* The value of authenticated_id is stored in the spool file and printed in
3577 log lines. It must not contain binary zeros or newline characters. In
3578 normal use, it never will, but when playing around or testing, this error
3579 can (did) happen. To guard against this, ensure that the id contains only
3580 printing characters. */
3581
3582 if (set_id) set_id = string_printing(set_id);
3583
3584 /* For the non-OK cases, set up additional logging data if set_id
3585 is not empty. */
3586
3587 if (rc != OK)
3588 set_id = set_id && *set_id
3589 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3590
3591 /* Switch on the result */
3592
3593 switch(rc)
3594 {
3595 case OK:
3596 if (!au->set_id || set_id) /* Complete success */
3597 {
3598 if (set_id) authenticated_id = string_copy_malloc(set_id);
3599 sender_host_authenticated = au->name;
3600 authentication_failed = FALSE;
3601 authenticated_fail_id = NULL; /* Impossible to already be set? */
3602
3603 received_protocol =
3604 (sender_host_address ? protocols : protocols_local)
3605 [pextend + pauthed + (tls_in.active >= 0 ? pcrpted:0)];
3606 *s = *ss = US"235 Authentication succeeded";
3607 authenticated_by = au;
3608 break;
3609 }
3610
3611 /* Authentication succeeded, but we failed to expand the set_id string.
3612 Treat this as a temporary error. */
3613
3614 auth_defer_msg = expand_string_message;
3615 /* Fall through */
3616
3617 case DEFER:
3618 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3619 *s = string_sprintf("435 Unable to authenticate at present%s",
3620 auth_defer_user_msg);
3621 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3622 set_id, auth_defer_msg);
3623 break;
3624
3625 case BAD64:
3626 *s = *ss = US"501 Invalid base64 data";
3627 break;
3628
3629 case CANCELLED:
3630 *s = *ss = US"501 Authentication cancelled";
3631 break;
3632
3633 case UNEXPECTED:
3634 *s = *ss = US"553 Initial data not expected";
3635 break;
3636
3637 case FAIL:
3638 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3639 *s = US"535 Incorrect authentication data";
3640 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3641 break;
3642
3643 default:
3644 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3645 *s = US"435 Internal error";
3646 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3647 "check", set_id, rc);
3648 break;
3649 }
3650
3651 return rc;
3652 }
3653
3654
3655
3656
3657
3658 static int
3659 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3660 {
3661 int rd;
3662 if (allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3663 {
3664 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3665 *recipient);
3666 rd = Ustrlen(recipient) + 1;
3667 *recipient = rewrite_address_qualify(*recipient, TRUE);
3668 return rd;
3669 }
3670 smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE,
3671 smtp_cmd_data);
3672 log_write(L_smtp_syntax_error,
3673 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3674 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3675 return 0;
3676 }
3677
3678
3679
3680
3681 static void
3682 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3683 {
3684 HAD(SCH_QUIT);
3685 incomplete_transaction_log(US"QUIT");
3686 if (acl_smtp_quit)
3687 {
3688 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3689 if (rc == ERROR)
3690 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3691 *log_msgp);
3692 }
3693 if (*user_msgp)
3694 smtp_respond(US"221", 3, TRUE, *user_msgp);
3695 else
3696 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
3697
3698 #ifdef SUPPORT_TLS
3699 tls_close(TRUE, TRUE);
3700 #endif
3701
3702 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3703 smtp_get_connection_info());
3704 }
3705
3706
3707 static void
3708 smtp_rset_handler(void)
3709 {
3710 HAD(SCH_RSET);
3711 incomplete_transaction_log(US"RSET");
3712 smtp_printf("250 Reset OK\r\n", FALSE);
3713 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3714 }
3715
3716
3717
3718 /*************************************************
3719 * Initialize for SMTP incoming message *
3720 *************************************************/
3721
3722 /* This function conducts the initial dialogue at the start of an incoming SMTP
3723 message, and builds a list of recipients. However, if the incoming message
3724 is part of a batch (-bS option) a separate function is called since it would
3725 be messy having tests splattered about all over this function. This function
3726 therefore handles the case where interaction is occurring. The input and output
3727 files are set up in smtp_in and smtp_out.
3728
3729 The global recipients_list is set to point to a vector of recipient_item
3730 blocks, whose number is given by recipients_count. This is extended by the
3731 receive_add_recipient() function. The global variable sender_address is set to
3732 the sender's address. The yield is +1 if a message has been successfully
3733 started, 0 if a QUIT command was encountered or the connection was refused from
3734 the particular host, or -1 if the connection was lost.
3735
3736 Argument: none
3737
3738 Returns: > 0 message successfully started (reached DATA)
3739 = 0 QUIT read or end of file reached or call refused
3740 < 0 lost connection
3741 */
3742
3743 int
3744 smtp_setup_msg(void)
3745 {
3746 int done = 0;
3747 BOOL toomany = FALSE;
3748 BOOL discarded = FALSE;
3749 BOOL last_was_rej_mail = FALSE;
3750 BOOL last_was_rcpt = FALSE;
3751 void *reset_point = store_get(0);
3752
3753 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3754
3755 /* Reset for start of new message. We allow one RSET not to be counted as a
3756 nonmail command, for those MTAs that insist on sending it between every
3757 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3758 TLS between messages (an Exim client may do this if it has messages queued up
3759 for the host). Note: we do NOT reset AUTH at this point. */
3760
3761 smtp_reset(reset_point);
3762 message_ended = END_NOTSTARTED;
3763
3764 chunking_state = chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3765
3766 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3767 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3768 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3769 #ifdef SUPPORT_TLS
3770 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3771 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
3772 #endif
3773
3774 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3775
3776 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3777
3778 /* Batched SMTP is handled in a different function. */
3779
3780 if (smtp_batched_input) return smtp_setup_batch_msg();
3781
3782 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3783 value. The values are 2 larger than the required yield of the function. */
3784
3785 while (done <= 0)
3786 {
3787 const uschar **argv;
3788 uschar *etrn_command;
3789 uschar *etrn_serialize_key;
3790 uschar *errmess;
3791 uschar *log_msg, *smtp_code;
3792 uschar *user_msg = NULL;
3793 uschar *recipient = NULL;
3794 uschar *hello = NULL;
3795 uschar *s, *ss;
3796 BOOL was_rej_mail = FALSE;
3797 BOOL was_rcpt = FALSE;
3798 void (*oldsignal)(int);
3799 pid_t pid;
3800 int start, end, sender_domain, recipient_domain;
3801 int ptr, size, rc;
3802 int c;
3803 auth_instance *au;
3804 uschar *orcpt = NULL;
3805 int flags;
3806
3807 #ifdef AUTH_TLS
3808 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3809 if ( tls_in.active >= 0
3810 && tls_in.peercert
3811 && tls_in.certificate_verified
3812 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3813 )
3814 {
3815 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3816 if ( acl_smtp_auth
3817 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3818 &user_msg, &log_msg)) != OK
3819 )
3820 {
3821 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3822 continue;
3823 }
3824
3825 for (au = auths; au; au = au->next)
3826 if (strcmpic(US"tls", au->driver_name) == 0)
3827 {
3828 smtp_cmd_data = NULL;
3829
3830 if (smtp_in_auth(au, &s, &ss) == OK)
3831 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3832 else
3833 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
3834 break;
3835 }
3836 }
3837 #endif
3838
3839 #ifdef TCP_QUICKACK
3840 if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */
3841 (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK,
3842 US &off, sizeof(off));
3843 #endif
3844
3845 switch(smtp_read_command(TRUE, GETC_BUFFER_UNLIMITED))
3846 {
3847 /* The AUTH command is not permitted to occur inside a transaction, and may
3848 occur successfully only once per connection. Actually, that isn't quite
3849 true. When TLS is started, all previous information about a connection must
3850 be discarded, so a new AUTH is permitted at that time.
3851
3852 AUTH may only be used when it has been advertised. However, it seems that
3853 there are clients that send AUTH when it hasn't been advertised, some of
3854 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3855 So there's a get-out that allows this to happen.
3856
3857 AUTH is initially labelled as a "nonmail command" so that one occurrence
3858 doesn't get counted. We change the label here so that multiple failing
3859 AUTHS will eventually hit the nonmail threshold. */
3860
3861 case AUTH_CMD:
3862 HAD(SCH_AUTH);
3863 authentication_failed = TRUE;
3864 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3865
3866 if (!auth_advertised && !allow_auth_unadvertised)
3867 {
3868 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3869 US"AUTH command used when not advertised");
3870 break;
3871 }
3872 if (sender_host_authenticated)
3873 {
3874 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3875 US"already authenticated");
3876 break;
3877 }
3878 if (sender_address)
3879 {
3880 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3881 US"not permitted in mail transaction");
3882 break;
3883 }
3884
3885 /* Check the ACL */
3886
3887 if ( acl_smtp_auth
3888 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3889 &user_msg, &log_msg)) != OK
3890 )
3891 {
3892 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3893 break;
3894 }
3895
3896 /* Find the name of the requested authentication mechanism. */
3897
3898 s = smtp_cmd_data;
3899 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3900 {
3901 if (!isalnum(c) && c != '-' && c != '_')
3902 {
3903 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3904 US"invalid character in authentication mechanism name");
3905 goto COMMAND_LOOP;
3906 }
3907 smtp_cmd_data++;
3908 }
3909
3910 /* If not at the end of the line, we must be at white space. Terminate the
3911 name and move the pointer on to any data that may be present. */
3912
3913 if (*smtp_cmd_data != 0)
3914 {
3915 *smtp_cmd_data++ = 0;
3916 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3917 }
3918
3919 /* Search for an authentication mechanism which is configured for use
3920 as a server and which has been advertised (unless, sigh, allow_auth_
3921 unadvertised is set). */
3922
3923 for (au = auths; au; au = au->next)
3924 if (strcmpic(s, au->public_name) == 0 && au->server &&
3925 (au->advertised || allow_auth_unadvertised))
3926 break;
3927
3928 if (au)
3929 {
3930 c = smtp_in_auth(au, &s, &ss);
3931
3932 smtp_printf("%s\r\n", FALSE, s);
3933 if (c != OK)
3934 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3935 au->name, host_and_ident(FALSE), ss);
3936 }
3937 else
3938 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3939 string_sprintf("%s authentication mechanism not supported", s));
3940
3941 break; /* AUTH_CMD */
3942
3943 /* The HELO/EHLO commands are permitted to appear in the middle of a
3944 session as well as at the beginning. They have the effect of a reset in
3945 addition to their other functions. Their absence at the start cannot be
3946 taken to be an error.
3947
3948 RFC 2821 says:
3949
3950 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3951 or 502 failure replies MUST be returned as appropriate. The SMTP
3952 server MUST stay in the same state after transmitting these replies
3953 that it was in before the EHLO was received.
3954
3955 Therefore, we do not do the reset until after checking the command for
3956 acceptability. This change was made for Exim release 4.11. Previously
3957 it did the reset first. */
3958
3959 case HELO_CMD:
3960 HAD(SCH_HELO);
3961 hello = US"HELO";
3962 esmtp = FALSE;
3963 goto HELO_EHLO;
3964
3965 case EHLO_CMD:
3966 HAD(SCH_EHLO);
3967 hello = US"EHLO";
3968 esmtp = TRUE;
3969
3970 HELO_EHLO: /* Common code for HELO and EHLO */
3971 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
3972 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
3973
3974 /* Reject the HELO if its argument was invalid or non-existent. A
3975 successful check causes the argument to be saved in malloc store. */
3976
3977 if (!check_helo(smtp_cmd_data))
3978 {
3979 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", FALSE, hello);
3980
3981 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
3982 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3983 (*smtp_cmd_argument == 0)? US"(no argument given)" :
3984 string_printing(smtp_cmd_argument));
3985
3986 if (++synprot_error_count > smtp_max_synprot_errors)
3987 {
3988 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3989 "syntax or protocol errors (last command was \"%s\")",
3990 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
3991 done = 1;
3992 }
3993
3994 break;
3995 }
3996
3997 /* If sender_host_unknown is true, we have got here via the -bs interface,
3998 not called from inetd. Otherwise, we are running an IP connection and the
3999 host address will be set. If the helo name is the primary name of this
4000 host and we haven't done a reverse lookup, force one now. If helo_required
4001 is set, ensure that the HELO name matches the actual host. If helo_verify
4002 is set, do the same check, but softly. */
4003
4004 if (!sender_host_unknown)
4005 {
4006 BOOL old_helo_verified = helo_verified;
4007 uschar *p = smtp_cmd_data;
4008
4009 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
4010 *p = 0;
4011
4012 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
4013 because otherwise the log can be confusing. */
4014
4015 if (sender_host_name == NULL &&
4016 (deliver_domain = sender_helo_name, /* set $domain */
4017 match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
4018 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
4019 (void)host_name_lookup();
4020
4021 /* Rebuild the fullhost info to include the HELO name (and the real name
4022 if it was looked up.) */
4023
4024 host_build_sender_fullhost(); /* Rebuild */
4025 set_process_info("handling%s incoming connection from %s",
4026 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
4027
4028 /* Verify if configured. This doesn't give much security, but it does
4029 make some people happy to be able to do it. If helo_required is set,
4030 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
4031 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
4032 now obsolescent, since the verification can now be requested selectively
4033 at ACL time. */
4034
4035 helo_verified = helo_verify_failed = sender_helo_dnssec = FALSE;
4036 if (helo_required || helo_verify)
4037 {
4038 BOOL tempfail = !smtp_verify_helo();
4039 if (!helo_verified)
4040 {
4041 if (helo_required)
4042 {
4043 smtp_printf("%d %s argument does not match calling host\r\n", FALSE,
4044 tempfail? 451 : 550, hello);
4045 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
4046 tempfail? "temporarily " : "",
4047 hello, sender_helo_name, host_and_ident(FALSE));
4048 helo_verified = old_helo_verified;
4049 break; /* End of HELO/EHLO processing */
4050 }
4051 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
4052 "helo_try_verify_hosts\n", hello);
4053 }
4054 }
4055 }
4056
4057 #ifdef EXPERIMENTAL_SPF
4058 /* set up SPF context */
4059 spf_init(sender_helo_name, sender_host_address);
4060 #endif
4061
4062 /* Apply an ACL check if one is defined; afterwards, recheck
4063 synchronization in case the client started sending in a delay. */
4064
4065 if (acl_smtp_helo)
4066 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
4067 &user_msg, &log_msg)) != OK)
4068 {
4069 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
4070 sender_helo_name = NULL;
4071 host_build_sender_fullhost(); /* Rebuild */
4072 break;
4073 }
4074 else if (!check_sync()) goto SYNC_FAILURE;
4075
4076 /* Generate an OK reply. The default string includes the ident if present,
4077 and also the IP address if present. Reflecting back the ident is intended
4078 as a deterrent to mail forgers. For maximum efficiency, and also because
4079 some broken systems expect each response to be in a single packet, arrange
4080 that the entire reply is sent in one write(). */
4081
4082 auth_advertised = FALSE;
4083 pipelining_advertised = FALSE;
4084 #ifdef SUPPORT_TLS
4085 tls_advertised = FALSE;
4086 #endif
4087 dsn_advertised = FALSE;
4088 #ifdef SUPPORT_I18N
4089 smtputf8_advertised = FALSE;
4090 #endif
4091
4092 smtp_code = US"250 "; /* Default response code plus space*/
4093 if (!user_msg)
4094 {
4095 s = string_sprintf("%.3s %s Hello %s%s%s",
4096 smtp_code,
4097 smtp_active_hostname,
4098 sender_ident ? sender_ident : US"",
4099 sender_ident ? US" at " : US"",
4100 sender_host_name ? sender_host_name : sender_helo_name);
4101
4102 ptr = Ustrlen(s);
4103 size = ptr + 1;
4104
4105 if (sender_host_address)
4106 {
4107 s = string_catn(s, &size, &ptr, US" [", 2);
4108 s = string_cat (s, &size, &ptr, sender_host_address);
4109 s = string_catn(s, &size, &ptr, US"]", 1);
4110 }
4111 }